KR20200040137A - Laminated film, and display device including same - Google Patents

Abstract

The present invention relates to a laminated film and a display apparatus comprising the laminated film, wherein the laminated film comprises: a light transmitting substrate; a hard coating layer; and an optical enhancement layer disposed between the light transmitting substrate and the hard coating layer, or facing the hard coating layer with the light transmitting substrate interposed between the optical enhancement layer and the hard coating layer, wherein the light transmitting substrate comprises polyimide, a poly(amide-imide) copolymer, or a combination thereof, and the optical enhancement layer comprises a copolymer of polyimide. The laminated film according to an embodiment can be usefully used as a window of a flexible display apparatus.

Description

Laminated film, and display device including laminated film {LAMINATED FILM, AND DISPLAY DEVICE INCLUDING SAME}

It relates to a laminated film and a display device comprising the laminated film.

Research into high performance and popularization of portable display devices such as smart phones and tablet PCs has been actively conducted. For example, research and development are underway to commercialize a lightweight flexible (ie, bendable or foldable) portable display device. A portable display device such as a liquid crystal display has a protective window for protecting a display module such as a liquid crystal layer. Currently, most portable display devices use a window including a hard glass substrate. However, since the glass can be easily broken by an external impact, it is not easily damaged when applied to a portable display device or the like and cannot be applied to a flexible display device because it has no flexible property. Accordingly, attempts have been made to replace the protective window with a plastic film in the display device.

However, plastic films need to further improve mechanical properties, such as hardness, and optical properties, for use in a protective window of a display device, and also require a high level of appearance quality.

One embodiment relates to a laminated film having improved interfacial reflection and interference fringe and improved optical properties and visibility.

Another embodiment relates to a display device including a laminated film with improved optical properties and visibility.

In one embodiment, the light-transmitting substrate; Hard coating layer; And an optical enhancement layer disposed between the light transmitting substrate and the hard coating layer or facing the hard coating layer with the light transmitting substrate interposed therebetween, wherein the light transmitting substrate is a polyimide. , Poly (amide-imide) copolymer, or a combination thereof, and the optical enhancement layer provides a laminated film comprising a copolymer of polyimide.

The refractive index of the optical enhancement layer has a value between the refractive index of the light transmitting substrate and the refractive index of the hard coating layer.

The optical enhancement layer has a refractive index between 1.5 and 1.7.

The polyimide copolymer of the optical enhancement layer may include (a) an imide structural unit, and (b) a urethane structural unit, a siloxane structural unit, an amide structural unit, or a combination thereof.

The imide structural unit may be represented by Formula 1 below:

(Formula 1)

In Chemical Formula 1,

D is a substituted or unsubstituted tetravalent C4 to C30 alicyclic organic group, a substituted or unsubstituted tetravalent C6 to C30 aromatic organic group, a substituted or unsubstituted tetravalent C4 to C30 heteroaromatic organic group, or these Is a combination of

The alicyclic organic group, the aromatic organic group, the heteroaromatic organic group, or a combination thereof is a monocyclic ring, a condensed ring in which two or more rings are fused, or two or more rings selected from the monocyclic and condensed rings Single bond, fluorenylene group, -O-, -S-, -C (= O)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,- (CH ₂ ) _p -,-(CF ₂ ) _q- , -C (C _n H _{2n + 1} ) _2- , -C (C _n F _{2n + 1} ) ₂ -,-(CH ₂ ) _p -C ( C _n H _{2n + 1} ) _2- (CH ₂ ) _q -,-(CH ₂ ) _p -C (C _n F _{2n + 1} ) _2- (CH ₂ ) _q- (where 1≤n≤10, 1≤ p≤10, and 1≤q≤10), -C (CF ₃ ) (C ₆ H ₅ )-, or -C (= O) NH-.

The urethane structural unit may be represented by the following formula (2):

(Formula 2)

*-(-Y-NH-CO-O-Z-)-*

In Chemical Formula 2,

Y and Z are each independently a substituted or unsubstituted divalent C1 to C30 aliphatic organic group, a substituted or unsubstituted divalent C2 to C30 alicyclic organic group, a substituted or unsubstituted C6 to C30 aromatic organic group, substituted or Unsubstituted C4 to C30 heteroaromatic organic group, or a combination thereof,

The alicyclic organic group, the aromatic organic group, the heteroaromatic organic group, or a combination thereof is a monocyclic ring, a condensed ring in which two or more rings are fused, or two or more rings selected from the monocyclic and condensed rings Single bond, fluorenylene group, -O-, -S-, -C (= O)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,- (CH ₂ ) _p -,-(CF ₂ ) _q- , -C (C _n H _{2n + 1} ) _2- , -C (C _n F _{2n + 1} ) ₂ -,-(CH ₂ ) _p -C ( C _n H _{2n + 1} ) _2- (CH ₂ ) _q -,-(CH ₂ ) _p -C (C _n F _{2n + 1} ) _2- (CH ₂ ) _q- (where 1≤n≤10, 1≤ p≤10, and 1≤q≤10), -C (CF ₃ ) (C ₆ H ₅ )-, or -C (= O) NH-.

The siloxane structural unit may be represented by the following formula (3):

(Formula 3)

In Chemical Formula 3,

R ^a to R ^f are each independently a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C2 to C30 alkenyl group, a substituted or unsubstituted C2 to C30 alkynyl group, a substituted or unsubstituted C1 to C30 An alkoxy group, a substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C6 to C30 aryl group, an epoxy group-containing group, or a combination thereof,

L ¹ and L ² are each independently a single bond, -O-, a substituted or unsubstituted C1 to C30 alkylene group, a substituted or unsubstituted C1 to C30 heteroalkylene group, a substituted or unsubstituted C2 to C30 alkenyl A alkylene group, a substituted or unsubstituted C3 to C30 cycloalkylene group, a substituted or unsubstituted C2 to C30 heterocycloalkylene group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C4 to C30 heteroaryl group, Or combinations thereof,

m is an integer from 0 to 150.

The amide structural unit may be represented by the following formula (4):

(Formula 4)

In Chemical Formula 4,

A, E ¹ and E ² are each independently a substituted or unsubstituted divalent C1 to C30 aliphatic organic group, a substituted or unsubstituted divalent C4 to C30 alicyclic organic group, or a substituted or unsubstituted divalent A C6 to C30 aromatic organic group, a substituted or unsubstituted divalent C4 to C30 heteroaromatic organic group, or a combination thereof,

The alicyclic organic group, aromatic organic group, heteroaromatic organic group, or a combination thereof may be a monocyclic ring, a condensed ring in which two or more rings are bonded, or two or more rings selected from the monocyclic and condensed ring may be a single bond. , Fluorenylene group, -O-, -S-, -C (= O)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,-(CH ₂ ) _p -,-(CF ₂ ) _q- , -C (C _n H _{2n + 1} ) _2- , -C (C _n F _{2n + 1} ) ₂ -,-(CH ₂ ) _p -C (C _n H _{2n + 1} ) _2- (CH ₂ ) _q -,-(CH ₂ ) _p -C (C _n F _{2n + 1} ) _2- (CH ₂ ) _q- (where 1≤n≤10, 1≤p≤ 10, and 1≤q≤10), -C (CF ₃ ) (C ₆ H ₅ )-, or -C (= O) NH-.

The optical enhancement layer may further include an incompletely condensed polyhedral oligomeric silsesquioxane (Polyhedral Oligmeric Silsesquioxane: POSS) in which one or more -Si-O-Si- bonds are introduced with hydrogen-bondable functional groups. have.

The partially condensed polyhedral oligomer silsesquioxane in which one or more -Si-O-Si- bonds are introduced with hydrogen-bondable functional groups may be represented by the following Chemical Formula 5 or Chemical Formula 6:

(Formula 5) (Formula 6)

In Chemical Formulas 5 and 6,

R are each independently a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C6 to C30 aryl group, or a combination thereof,

R 'is each independently -OH, -SH, or -NH ₂ .

The one or more -Si-O-Si- partial condensed polyhedral oligomer silsesquioxane in which a hydrogen-bondable functional group is introduced at a broken position may be included in an amount of 20 parts by mass or less per 100 parts by mass of the polyimide copolymer in the optical improvement layer. have.

The hard coating layer may include a silicone polymer, a urethane polymer, an acrylic polymer, an epoxy polymer, or a combination thereof.

The hard coating layer may include a silicone-based polymer, and the silicone-based polymer may include an organopolysiloxane.

The light-transmitting substrate is a polyimide comprising an imide structural unit represented by Chemical Formula 1 or an imide structural unit represented by Chemical Formula 1 and an amide structural unit represented by Chemical Formula 4 below. Imide) copolymers, or combinations thereof:

(Formula 1)

(Formula 4)

Formula 1 and Formula 4 are as defined above.

The thickness of the light transmitting substrate is 30 μm to 300 μm, the thickness of the hard coating layer is 1 μm to 30 μm, and the thickness of the optical enhancement layer may be 0.1 μm to 10 μm.

The transmittance of the laminated film may be 90% or more.

YI of the laminated film may be less than 3.

The haze of the laminated film may be 2 or less.

After attaching the laminated film to the black reflector, when measuring reflectance at an incident angle of 45 degrees, the laminated film may have an average amplitude of 0.1% or less in the visible light region.

Another embodiment relates to a display device including a laminated film according to the embodiment.

The laminated film according to one embodiment suppresses the occurrence of interfacial reflection and interference fringe, thereby improving light characteristics and visibility, and thus exhibiting excellent appearance quality, and thus can be usefully used as a window of a flexible display device.

1 is a view showing a schematic cross-section of a laminated film in which the light transmitting substrate 100, the optical enhancement layer 200, and the hard coating layer 300 are sequentially stacked according to one embodiment.
2 is a view showing a schematic cross-section of a laminated film in which the optical enhancement layer 200, the light transmitting substrate 100, and the hard coating layer 300 are sequentially stacked according to another embodiment.
3 is a view showing a schematic cross-section of a laminated film further comprising a back coating layer 400 on the lower surface of the light transmitting substrate 100 of the laminated film of FIG. 1 according to another embodiment,
4 is a view showing a schematic cross-section of a laminated film further comprising a back coating layer 400 on the lower surface of the optical enhancement layer 200 of the laminated film of FIG. 2 according to another embodiment,
5 is a view showing a schematic cross-section of a laminated film further comprising a binder or a superelastic layer 500 under the back coating layer 400 of the laminated film of FIG. 3 according to another embodiment,
6 is a view showing a schematic cross-section of a laminated film further comprising a binder or a superelastic layer 500 under the back coating layer 400 of the laminated film of FIG. 4 according to another embodiment,
7 is a view showing a schematic cross-section of a laminated film further comprising an adhesive or a superelastic layer 500 under the light transmitting substrate 100 of the laminated film of FIG. 1 according to another embodiment,
8 is a view showing a schematic cross-section of a laminated film further comprising an adhesive or a superelastic layer 500 under the optical enhancement layer 200 of the laminated film of FIG. 2 according to another embodiment.

Hereinafter, embodiments of the present invention will be described in detail. However, this is provided as an example, and the present invention is not limited thereby, and the present invention is only defined by the scope of claims to be described later.

Unless otherwise specified in the present specification, "substitution" means that one or more hydrogen atoms included in a given functional group are halogen atoms (F, Cl, Br or I), hydroxyl groups, nitro groups, cyano groups, amino groups (- NH ₂ , -NH (R ¹⁰⁰ ), or -N (R ¹⁰¹ ) (R ¹⁰² ), where R ¹⁰⁰ , R ¹⁰¹ and R ¹⁰² are the same or different from each other, each independently being a C1 to C10 alkyl group), ami Dino group, hydrazine group, hydrazone group, carboxyl group, ester group, ketone group, substituted or unsubstituted alkyl group, substituted or unsubstituted alicyclic organic group (for example, cycloalkyl group, etc.), substituted or unsubstituted aryl group ( For example, a benzyl group, a naphthyl group, a fluorenyl group, etc.), a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted heteroaryl group, and a substituted or unsubstituted heterocyclic group Substitute with one or more substituents selected from the group Means, and said substituents may form a ring are connected to each other.

Unless otherwise specified in this specification, "alkyl group" means a C1 to C30 alkyl group, specifically means a C1 to C15 alkyl group, and "cycloalkyl group" means a C3 to C30 cycloalkyl group, specifically C3 To C18 cycloalkyl group, "alkoxy group" means a C1 to C30 alkoxy group, specifically means a C1 to C18 alkoxy group, and "ester group" means a C2 to C30 ester group, specifically C2 to C18 ester group means, "ketone group" means a C2 to C30 ketone group, specifically means a C2 to C18 ketone group, and "aryl group" means a C6 to C30 aryl group, specifically C6 to C18 aryl Means a C2 to C30 alkenyl group, and specifically means a C2 to C18 alkenyl group.

Unless otherwise specified in this specification, "combination" means mixing or copolymerization. In this case, "copolymerization" means random copolymerization, block copolymerization, or graft copolymerization.

In this specification, the term "polyimide" does not only mean "polyimide", but may mean "polyimide", "polyamic acid", or a combination thereof. In addition, "polyimide" and "polyamic acid" can be used interchangeably as having the same meaning.

In addition, in this specification, "*" means a part connected to the same or different atom or chemical formula.

In the drawings, thicknesses are enlarged to clearly represent various layers and regions. The same reference numerals are used for similar parts throughout the specification. When a portion of a layer, film, region, plate, or the like is said to be "above" another portion, this includes not only the case "directly above" the other portion, but also another portion in the middle. Conversely, when one part is "just above" another part, it means that there is no other part in the middle.

One embodiment relates to a laminated film that can be used as a cover window or the like for protecting a display device such as a flexible display device or a foldable display device.

Conventional glass substrates have been used to protect the elements of a display device, but in order to have flexible and foldable characteristics in which the shape is freely bent, while having strength and hardness as a window of the display device, a function as a display element can be exhibited. It is essential to use a plastic material that has light transmittance and color similar to that of the glass substrate. A cover window for a display device is required to have a high level of appearance quality, along with high light characteristics, durability, and flexibility.

As a plastic material, research has been conducted using a polyimide-based transparent film that has high durability and heat resistance, and can also meet optical properties to some extent. Here, a laminated film in which a hard coating layer is added on a polyimide substrate to obtain a hardness as high as glass has been attempted. However, an interference phenomenon occurs due to the lamination of two layers having different refractive indices, and the difference in thickness and refractive index of each layer intensifies the interference phenomenon, causing a strong rainbow phenomenon on the film surface. Even if the intrinsic properties of the material such as the refractive index are the same, as a result of the film forming process, coating process, etc., thickness variation or material may be mixed in the entire film, which may deform the rainbow phenomenon. As a result, the rainbow phenomenon of the optical film is a phenomenon in which a wide area of the film has a different reflectance or a different viewing angle depending on the position, and can be observed with the naked eye.

It is known that the rainbow phenomenon of the optical film does not appear when the reflectance ripple amplitude is less than 1% in the wavelength region of 500 nm to 600 nm, or when the maximum amplitude is less than 0.5% in the entire visible light region. However, since the existing reflectance measurement is measured in a wide measurement area of several mm or more, a small change in reflectance according to the location is added, and the inherent reflectance ripple causing the rainbow phenomenon is not canceled out, and also at a low reflection angle of 10 ° or less As it is observed, there is a distance from the rainbow phenomenon measured by the naked eye.

In one embodiment, in a laminated film including a light-transmitting substrate and a hard coating layer, the generation of interfacial reflection and interference fringes at the interlayer interface is suppressed, thereby providing a laminated film with improved optical properties and visibility. The laminated film according to one embodiment, after attaching the laminated film to the black reflector, when measuring reflectance at an angle of incidence of 45 degrees, the average amplitude in the visible light region is lower than 0.1%, so the surface rainbow phenomenon hardly occurs and light It may be a laminated film with improved properties and visibility.

In one embodiment, the laminated film, a light transmitting substrate; Hard coating layer; And an optical enhancement layer disposed between the light transmitting substrate and the hard coating layer or facing the hard coating layer with the light transmitting substrate interposed therebetween, wherein the light transmitting substrate comprises polyimide, poly ( Amide-imide) copolymer, or a combination thereof, and the optical enhancement layer comprises a copolymer of polyimide.

1 and 2 schematically show cross-sections of a laminated film according to an embodiment.

Referring to FIG. 1, on the light-transmitting substrate 100 including a polyimide, poly (amide-imide) copolymer, or a combination thereof, an optical enhancement layer 200 including a copolymer of polyimide is present. And, a hard coating layer 300 may be present on the optical enhancement layer 200.

Referring to FIG. 2, a hard coating layer 300 is directly disposed on a light-transmitting substrate 100 including a polyimide, poly (amide-imide) copolymer, or a combination thereof, and the light-transmitting substrate ( An optical enhancement layer 200 including a copolymer of polyimide may be present on a surface opposite to the surface on which the hard coating layer 300 of 100) is disposed.

The laminated film according to FIGS. 1 and 2 is the same in that it includes a light transmitting substrate 100, a hard coating layer 300, and an optical improving layer 200, but the optical improving layer 200 is a light transmitting substrate It is present between (100) and the hard coating layer 300 (FIG. 1), or the optical enhancement layer 200 is located at a position facing the hard coating layer 300 with the light transmitting substrate 100 therebetween. (FIG. 2), there is a difference in the position of the optical enhancement layer 200 in the laminated film. As described above, although the optical enhancement layer 200 is present at different positions in the laminated film, as can be clearly seen from the examples and comparative examples described below, two cases including the optical enhancement layer 200 In all, when observing the laminated film on the surface of the laminated film, that is, the hard coating side, the rainbow phenomenon hardly occurs compared to the laminated film that does not include the optical enhancement layer 200.

The optical enhancement layer 200 has a refractive index between the refractive index of the light transmitting substrate 100 and the refractive index of the hard coating layer 300. In this case, the laminated film according to the embodiment does not exhibit a rainbow phenomenon, and visibility and optical characteristics are improved.

In one embodiment, the optical enhancement layer 200 may have a refractive index between 1.5 and 1.7. This is, the laminate film according to one embodiment includes a polyimide-based film as the light transmitting substrate 100, and a silicone-based polymer, a urethane-based polymer, an acrylic-based polymer, an epoxy-based polymer, or a combination thereof as the hard coating layer 300. When included, since the refractive index of the polyimide-based film is between about 1.55 to about 1.75, and the refractive index of the hard coating layer is between about 1.5 to about 1.6, the optical enhancement layer 200 has a value between the refractive index values of the two layers. It is adjusted to have.

In one embodiment, the light transmissive substrate 100 can have a refractive index between 1.6 and 1.75, for example, between 1.65 and 1.72, for example between 1.67 and 1.7, and the hard coating layer 300 ) Is a refractive index between 1.5 and 1.6, e.g., a refractive index between 1.5 and 1.59, e.g., a refractive index between 1.5 and 1.57, e.g., a refractive index between 1.5 and 1.55, e.g., a refractive index between 1.5 and 1.53, e.g. For example, it may have a refractive index of 1.5 to 1.52, and the optical enhancement layer 200 may have a refractive index of 1.5 to 1.7, for example, a refractive index of 1.52 to 1.68, for example, a refractive index of 1.55 to 1.65. For example, it may have a refractive index of 1.57 to 1.63, for example, a refractive index of 1.58 to 1.61, for example, a refractive index of 1.58 to 1.6, the refractive index of the optical enhancement layer 200 of the light transmitting substrate 100 On the premise that it has a value between the refractive index and the refractive index of the hard coating layer 300, Refractive index value of each layer-layer film is not limited to the above value.

The polyimide copolymer included in the optical enhancement layer may include (a) an imide structural unit, and (b) a urethane structural unit, a siloxane structural unit, an amide structural unit, or a combination thereof.

For example, the optical enhancement layer may include a poly (imide-urethane) copolymer comprising an imide structural unit and a urethane structural unit.

Alternatively, the optical enhancement layer may include a poly (imide-siloxane) copolymer comprising an imide structural unit and a siloxane structural unit.

Alternatively, the optical enhancement layer may include a poly (imide-amide) copolymer comprising an imide structural unit and an amide structural unit.

Alternatively, the optical enhancement layer may include a copolymer comprising (a) an imide structural unit, and (b) a urethane structural unit, a siloxane structural unit, and an amide structural unit of two or more structural units.

Alternatively, the optical improvement layer may include a copolymer comprising all of an imide structural unit, a urethane structural unit, a siloxane structural unit, and an amide structural unit.

The imide structural unit may be represented by Formula 1 below:

(Formula 1)

In Chemical Formula 1,

D is a substituted or unsubstituted tetravalent C4 to C30 alicyclic organic group, a substituted or unsubstituted tetravalent C6 to C30 aromatic organic group, or a substituted or unsubstituted tetravalent C4 to C30 heteroaromatic organic group, or Combination of these,

The alicyclic organic group, the aromatic organic group, the heteroaromatic organic group, or a combination thereof is a monocyclic ring, a condensed ring in which two or more rings are fused, or two or more rings selected from the monocyclic and condensed rings Single bond, fluorenylene group, -O-, -S-, -C (= O)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,- (CH ₂ ) _p -,-(CF ₂ ) _q- , -C (C _n H _{2n + 1} ) _2- , -C (C _n F _{2n + 1} ) ₂ -,-(CH ₂ ) _p -C ( C _n H _{2n + 1} ) _2- (CH ₂ ) _q -,-(CH ₂ ) _p -C (C _n F _{2n + 1} ) _2- (CH ₂ ) _q- (where 1≤n≤10, 1≤ p≤10, and 1≤q≤10), -C (CF ₃ ) (C ₆ H ₅ )-, or -C (= O) NH-.

D of Formula 1 may be selected from the formula represented by Group 1 below:

(Group 1)

In the above equations,

Each residue may be substituted or unsubstituted, and each L is the same or different, and each independently, a single bond, a fluorenylene group, -O-, -S-, -C (= O)-,- CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,-(CH ₂ ) _p - _, -(CF ₂ ) _q- , -C (C _n H _{2n + 1} ) _2- , -C (C _n F _{2n + 1} ) ₂ -,-(CH ₂ ) _p -C (C _n H _{2n + 1} ) _2- (CH ₂ ) _q -,-(CH ₂ ) _p -C ( C _n F _{2n + 1} ) _2- (CH ₂ ) _q- (where 1≤n≤10, 1≤p≤10, and 1≤q≤10), -C (CF ₃ ) (C ₆ H ₅ )- , Or -C (= O) NH-,

* Is a part connected to an adjacent atom,

Z ¹ and Z ² are the same or different, respectively, and independently, -N = or -C (R ¹⁰⁰ ) =, R ¹⁰⁰ is hydrogen or a C1 to C5 alkyl group, and Z ¹ and Z ² are simultaneously -C (R ¹⁰⁰ ) = not,

Z ³ is -O-, -S-, or -NR ^101- , where R ¹⁰¹ is hydrogen or a C1 to C5 alkyl group.

Formulas represented by Group 1 may be represented by Formulas of Group 2 below, but are not limited to these:

(Group 2)

In one embodiment, the imide structural unit represented by Chemical Formula 1 may be represented by Chemical Formula 1-1:

(Formula 1-1)

In Chemical Formula 1-1, L is the same as defined for Chemical Formula of Group 1.

In one embodiment, the imide structural unit represented by Chemical Formula 1 is represented by Chemical Formula 1-1, where L is a single bond, -C (C _n H _{2n + 1} ) _2- , -C (C _n F _{2n + 1} ) ₂ -,-(CH ₂ ) _p -C (C _n H _{2n + 1} ) _2- (CH ₂ ) _q- , or-(CH ₂ ) _p -C (C _n F _{2n + 1} ) _2- (CH ₂ ) _q- (where 1≤n≤10, 1≤p≤10, and 1≤q≤10), for example, when the formula 1-1 is L is a single bond , And L is -C (C _n F _{2n + 1} ) _2- (where 1≤n≤10).

In one embodiment, Chemical Formula 1-1 may be a combination when L is a single bond and when L is -C (CF ₃ ) _2- .

The urethane structural unit may be represented by the following formula (2):

(Formula 2)

*-(-Y-NH-CO-O-Z-)-*

In Chemical Formula 2,

Y and Z are each independently substituted or unsubstituted divalent C1 to C30 aliphatic organic group, substituted or unsubstituted divalent C2 to C30 alicyclic organic group, substituted or unsubstituted C6 to C30 aromatic organic group, or substituted Or an unsubstituted C4 to C30 heteroaromatic organic group, or a combination thereof,

The alicyclic organic group, the aromatic organic group, the heteroaromatic organic group, or a combination thereof is a monocyclic ring, a condensed ring in which two or more rings are fused, or two or more rings selected from the monocyclic and condensed rings Single bond, fluorenylene group, -O-, -S-, -C (= O)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,- (CH ₂ ) _p -,-(CF ₂ ) _q- , -C (C _n H _{2n + 1} ) _2- , -C (C _n F _{2n + 1} ) ₂ -,-(CH ₂ ) _p -C ( C _n H _{2n + 1} ) _2- (CH ₂ ) _q -,-(CH ₂ ) _p -C (C _n F _{2n + 1} ) _2- (CH ₂ ) _q- (where 1≤n≤10, 1≤ p≤10, and 1≤q≤10), -C (CF ₃ ) (C ₆ H ₅ )-, or -C (= O) NH-.

In one embodiment, Y is a substituted or unsubstituted divalent alicyclic organic group, or a substituted or unsubstituted divalent aromatic organic group, and may be, for example, a substituted divalent alicyclic organic group.

In one embodiment, Z is a substituted or unsubstituted divalent C1 to C30 aliphatic organic group, or a substituted or unsubstituted divalent aromatic organic group, for example, a substituted or unsubstituted divalent C1 to C20 aliphatic It may be an organic group. In one embodiment, Z may be a substituted or unsubstituted divalent C1 to C10 alkylene group.

The siloxane structural unit may be represented by the following formula (3):

(Formula 3)

In Chemical Formula 3,

R ^a to R ^f are each independently a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C2 to C30 alkenyl group, a substituted or unsubstituted C2 to C30 alkynyl group, a substituted or unsubstituted C1 to C30 An alkoxy group, a substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C6 to C30 aryl group, an epoxy group-containing group, or a combination thereof,

L ¹ and L ² are each independently a single bond, -O-, a substituted or unsubstituted C1 to C30 alkylene group, a substituted or unsubstituted C1 to C30 heteroalkylene group, a substituted or unsubstituted C2 to C30 alkenyl A alkylene group, a substituted or unsubstituted C3 to C30 cycloalkylene group, a substituted or unsubstituted C2 to C30 heterocycloalkylene group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C4 to C30 heteroaryl group, Or combinations thereof,

m is an integer from 0 to 150.

In one embodiment, R ^a to R ^f in Formula 3 are each independently a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C6 to C30 aryl group, or a combination thereof, L ¹ and L ² are each independently a single bond, -O-, a substituted or unsubstituted C1 to C30 alkylene group, a substituted or unsubstituted C6 to C30 arylene group, or a combination thereof, and m is one of an integer from 0 to 30 You can.

In one embodiment, R ^a to R ^f in Formula 3 are each independently, a substituted or unsubstituted C1 to C4 alkyl group, a substituted or unsubstituted phenyl group, or a combination thereof, and L ¹ and L ² are each independently As a single bond, -O-, a substituted or unsubstituted C1 to C10 alkylene group, a substituted or unsubstituted phenylene group, or a combination thereof, m may be an integer from 0 to 10.

The amide structural unit may be represented by the following formula (4):

 (Formula 4)

In Chemical Formula 4,

A, E ¹ and E ² are each independently a substituted or unsubstituted divalent C1 to C30 aliphatic organic group, a substituted or unsubstituted divalent C4 to C30 alicyclic organic group, or a substituted or unsubstituted divalent A C6 to C30 aromatic organic group, a substituted or unsubstituted divalent C4 to C30 heteroaromatic organic group, or a combination thereof,

The alicyclic organic group, aromatic organic group, heteroaromatic organic group, or a combination thereof may be a monocyclic ring, a condensed ring in which two or more rings are bonded, or two or more rings selected from the monocyclic and condensed ring may be a single bond. , Fluorenylene group, -O-, -S-, -C (= O)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,-(CH ₂ ) _p -,-(CF ₂ ) _q- , -C (C _n H _{2n + 1} ) _2- , -C (C _n F _{2n + 1} ) ₂ -,-(CH ₂ ) _p -C (C _n H _{2n + 1} ) _2- (CH ₂ ) _q -,-(CH ₂ ) _p -C (C _n F _{2n + 1} ) _2- (CH ₂ ) _q- (where 1≤n≤10, 1≤p≤ 10, and 1≤q≤10), -C (CF ₃ ) (C ₆ H ₅ )-, or -C (= O) NH-.

In one embodiment, A may be a substituted or unsubstituted divalent C6 to C30 aromatic organic group, wherein the aromatic organic group is a monocyclic ring, a condensed ring in which two or more rings are fused, or from the monocyclic and condensed ring 2 or more selected rings have a single bond, -O-, -S-, -C (= O)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) _2- , -(CH ₂ ) _p -,-(CF ₂ ) _q- , -C (C _n H _{2n + 1} ) _2- , -C (C _n F _{2n + 1} ) ₂ -,-(CH ₂ ) _p -C (C _n H _{2n + 1} ) _2- (CH ₂ ) _q -,-(CH ₂ ) _p -C (C _n F _{2n + 1} ) _2- (CH ₂ ) _q- (where 1≤n≤10, 1 ≤p≤10, and 1≤q≤10), -C (CF ₃ ) (C ₆ H ₅ )-, or -C (= O) NH-.

In one embodiment, A may be selected from the formula represented by Group 3 below:

(Group 3)

In the above formula,

R ¹⁸ to R ²⁹ are the same or different from each other, and each independently deuterium, halogen, a substituted or unsubstituted C1 to C10 aliphatic organic group, or a substituted or unsubstituted C6 to C20 aromatic organic group,

n11 and n14 to n20 are each independently an integer of 0 to 4,

n12 and n13 are each independently an integer of 0 to 3.

In one embodiment, A may be selected from the formula represented by Group 4 below:

(Group 4)

In one embodiment, A may be a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group, or a combination thereof.

In one embodiment, each of E ¹ and E ² is, independently, a substituted or unsubstituted divalent C6 to C30 aromatic organic group, and the substituted or unsubstituted divalent C6 to C30 aromatic organic group is monocyclic, or Two or more rings are fused condensed rings, or two or more selected from the monocyclic and condensed rings are single bonds, -O-, -S-, -C (= O)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,-(CH ₂ ) _p -,-(CF ₂ ) _q- , -C (C _n H _{2n + 1} ) _2- , -C (C _n F _{2n + 1} ) ₂ -,-(CH ₂ ) _p -C (C _n H _{2n + 1} ) _2- (CH ₂ ) _q -,-(CH ₂ ) _p -C (C _n F _{2n + 1} ) ₂ -(CH ₂ ) _q- (where 1≤n≤10, 1≤p≤10, and 1≤q≤10), -C (CF ₃ ) (C ₆ H ₅ )-, or -C (= O) It is a group linked by NH-.

In one embodiment, each of E ¹ and E ² is, independently, two or more substituted or unsubstituted aromatic monocycles are groups connected by a single bond, and / or substituted or unsubstituted two or more aromatic monocyclic rings -O-, -S-,-(CH ₂ ) _p- , or-(CF ₂ ) _q- (where 1≤p≤10, and 1≤q≤10).

In one embodiment, each of E ¹ and E ² is, independently, two or more phenylenes each substituted with an electron withdrawing group, for example, a haloalkyl group, for example, a trifluoromethyl group. A group linked by a single bond, and / or an alkyl group substituted by a hydroxy group and a haloalkyl group, for example, two or more phenylene groups each substituted by a methyl group substituted by a hydroxy group and a trifluoromethyl group It may be an alkylene group, for example, a group linked by a methylene group.

In one embodiment, E ¹ and E ² , each independently, may be a group represented by the following formula (7) or formula (8):

(Formula 7)

(Formula 8)

In one embodiment, the polyimide copolymer contained in the optical improving layer is a structure comprising (a) an imide structural unit, and (b) a urethane structural unit, a siloxane structural unit, an amide structural unit, or a combination thereof. Units may be included in a molar ratio of about 30 to 90: about 70 to 10. For example, the molar ratio of the total amount of the imide structural unit and the structural units other than the imide structural unit is about 35 to about 85: about 65 to about 15, for example, about 40 to about 80: about 60 to about 20 , For example, from about 45 to about 75: from about 55 to about 25, such as from about 50 to about 70: from about 50 to about 30, such as from about 50 to about 60: from about 50 to about 40 It can contain as.

A polyimide copolymer comprising an imide structural unit, a structural unit composed of other urethane structural units, siloxane structural units, amide structural units, or a combination thereof in the molar ratio, transmits light in a laminated film according to one embodiment The optical enhancement layer 200 having a refractive index value between the substrate 100 and the hard coating layer 300 may be advantageously manufactured.

The optical enhancement layer 200 includes at least one -Si- in addition to a polyimide-based copolymer including an imide structural unit, and other structural units composed of a urethane structural unit, a siloxane structural unit, an amide structural unit, or a combination thereof. It may further include an incompletely condensed polyhedral oligomeric silsesquioxane (Polyhedral Oligmeric Silsesquioxane: POSS) in which a functional group capable of hydrogen bonding is introduced at a position where the O-Si- bond is broken.

In one embodiment, the at least one -Si-O-Si- bond is a partially condensed polyhedral oligomer silsesquioxane in which a hydrogen-bondable functional group is introduced at a broken position may be represented by Formula 5 or Formula 6:

(Formula 5) (Formula 6)

In Chemical Formula 5 and Chemical Formula 6,

R are each independently a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C6 to C30 aryl group, or a combination thereof,

R 'is each independently -OH, -SH, or -NH ₂ .

The optically improved layer 200 is a partially condensed polyhedral oligomer yarn in which a functional group capable of hydrogen bonding is introduced at a position where the -Si-O-Si- bond of the partially condensed polyhedral oligomer silsesquioxane, as in Chemical Formula 5 or Chemical Formula 6, is broken When sesquioxane is further included, the mechanical strength of the layer is further increased and the yellowness is further lowered, thereby providing an optical improvement layer having excellent mechanical properties and optical properties.

The partially condensed polyhedral oligomer silsesquioxane in which at least one of the -Si-O-Si- bonds are introduced with hydrogen-bondable functional groups is 20 parts by mass or less per 100 parts by mass of the polyimide copolymer in the optical improvement layer 200, For example, 15 parts by mass or less per 100 parts by mass of the polyimide copolymer, for example, 10 parts by mass or less per 100 parts by mass of the polyimide copolymer, for example, about 1 part by mass to about 10 parts by mass You can.

In one embodiment, R of Formula 5 and Formula 6, each independently, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C3 to C10 cycloalkyl group, a substituted or unsubstituted C6 to C10 aryl group , Or a combination thereof, and R 'may each independently be -OH, or -NH ₂ .

In one embodiment, R of Formula 5 and Formula 6 may each independently be a phenyl group, a C1 to C4 alkyl group, or a combination thereof, and R 'may be -OH.

In one embodiment, the compound represented by Formula 5 and Formula 6 may be represented by Formula 5-1 and Formula 6-1, respectively:

(Formula 5-1)

(Formula 6-1)

In another embodiment, the optical enhancement layer 200 may further include an additive having a light absorption function in order to improve visibility and quality of a laminated film according to one embodiment. As the additive having the light absorption function, for example, a blueing agent may be included. The blueing agent is an additive that absorbs light in a wavelength range, such as from yellow to yellow, and adjusts color, for example, in the visible light region. For example, inorganic dyes or pigments such as ultramarine blue, royal blue, and cobalt blue, For example, organic dyes and pigments, such as a phthalocyanine-based blueing agent and a condensed polycyclic blueing agent, may be mentioned. Although the blueing agent is not particularly limited, from the viewpoint of heat resistance, light resistance, and solubility, a condensed polycyclic blueing agent may be used, for example, an anthraquinone-based blueing agent, and from the viewpoint of heat resistance, the blueing agent is heat of 200 ° C. or higher. What has a decomposition temperature can be used. Examples of the condensed polycyclic blueing agent include, but are not limited to, anthraquinone blueing agents, indigo blueing agents, phthalocyanine blueing agents, and the like, and the blueing agent is usually used as a blueing agent in the resin material field. It can be appropriately selected from those used.

When the optical improving layer 200 contains a blueing agent, the amount of the blueing agent added may be appropriately selected depending on the type of the blueing agent. For example, the polyimide-based copolymer solid content forming the optical improving layer 200 0.01 parts by mass or more, for example, 0.02 parts by mass or more, for example, 0.03 parts by mass or more, and 1.0 parts by mass or less, for example, 0.5 parts by mass or less, for example, 0.2 parts by mass It can include below.

The optical enhancement layer has a thickness of 0.1 μm to 10 μm, for example, 0.1 μm to 8 μm, for example, 0.1 μm to 7 μm, for example, 0.1 μm to 5 μm, for example, 0.3 μm to 5 μm, for example 0.5 μm to 5 μm, for example 0.5 μm to 3 μm, for example 0.5 μm to 2.5 μm, for example 0.5 μm to 2 μm, for example 0.5 μm to 1.5 μm, for example, 1 μm.

The light transmitting substrate 100 included in the laminated film according to the embodiment may include polyimide and / or poly (imide-amide) copolymer.

Polyimide or poly (amide-imide) copolymer film is useful as a display substrate material due to its high light transmittance, thermal stability, mechanical strength, and flexibility, but has recently been used in mobile devices such as smartphones and tablet PCs. Attempts have been made to use it as a high hardness window film that replaces the topmost glass, and accordingly it has been studied to have higher mechanical properties and optical properties. On the other hand, in the case of such a polyimide or poly (imide-amide) copolymer film, the refractive index is higher than that of a cellulose ester film, for example, a cellulose triacetate film. Therefore, when a polyimide or poly (imide-amide) copolymer film is used as a light transmitting substrate such as a window film, a hard coating layer having a low refractive index placed on the light transmitting substrate to compensate for the mechanical properties of the light transmitting substrate and A rainbow phenomenon may occur due to interfacial reflection due to a difference in refractive index and light interference. In one embodiment, by introducing the optical enhancement layer 200 as described above, the light-transmitting substrate 100 comprising a polyimide or poly (imide-amide) copolymer and the mechanical properties of the light-transmitting substrate 100 To prevent or prevent the rainbow phenomenon of the laminated film including the hard coating layer 300 applied to complement the physical properties, thereby providing an optical laminate with improved optical properties and color visibility.

The polyimide or poly (imide-amide) copolymer that can be used as the light transmitting substrate 100 in the laminated film according to one embodiment is suitable for use as an optical film, for example, a window film of a display device, etc. When it has mechanical properties and optical properties, it is not limited or limited to a specific type, and various types of polyimide or poly (imide-amide) copolymers known in the art can be used without limitation. In one embodiment, as a polyimide or poly (imide-amide) copolymer having excellent optical properties and mechanical properties, a polyimide comprising an imide structural unit represented by Formula 1 below, and / or the imide In addition to the structural unit, a poly (imide-amide) copolymer comprising an amide structural unit represented by Formula 4 may be included:

(Formula 1)

(Formula 4)

Since Formula 1 and Formula 4 are the same as defined above, detailed description thereof will be omitted.

In one embodiment, the imide structural unit represented by Chemical Formula 1 may include, but is not limited to, an imide structural unit represented by Chemical Formula 1-1:

(Formula 1-1)

In Chemical Formula 1-1,

L is the same or different, and each independently, a single bond, a fluorenylene group, -O-, -S-, -C (= O)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,-(CH ₂ ) _p - _, -(CF ₂ ) _q- , -C (C _n H _{2n + 1} ) _2- , -C (C _n F _{2n + 1} ) ₂ -,-(CH ₂ ) _p -C (C _n H _{2n + 1} ) _2- (CH ₂ ) _q -,-(CH ₂ ) _p -C (C _n F _{2n + 1} ) _2- (CH ₂ ) _q -(Where 1≤n≤10, 1≤p≤10, and 1≤q≤10), -C (CF ₃ ) (C ₆ H ₅ )-, or -C (= O) NH-,

* Is a part connected to an adjacent atom.

In one embodiment, Chemical Formula 1-1 may be a combination when L is a single bond and when L is -C (CF ₃ ) _2- , but is not limited thereto.

In one embodiment, the amide structural unit represented by Formula 4 is a substituted or unsubstituted phenylene group in which A of Formula 4 is substituted and / or a substituted or unsubstituted biphenylene group, and E ¹ and E ² are each Independently, it may be a group represented by Formula 7 and / or an amide structural unit represented by Formula 8 below, but is not limited to:

(Formula 7)

(Formula 8)

In addition to the polyimide containing the imide structural unit or the poly (imide-amide) copolymer containing the imide structural unit and the amide structural unit, the light transmitting substrate 100 may include one or more -Si-O-Si- bonds It may further include an incompletely condensed polyhedral oligomeric silsesquioxane (POSS) in which a functional group capable of hydrogen bonding is introduced at this broken position.

In one embodiment, the at least one -Si-O-Si- bond is a partially condensed polyhedral oligomer silsesquioxane in which a hydrogen-bondable functional group is introduced at a broken position may be represented by Formula 5 or Formula 6:

(Formula 5) (Formula 6)

In Chemical Formula 5 and Chemical Formula 6,

R are each independently a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C6 to C30 aryl group, or a combination thereof,

R 'is each independently -OH, -SH, or -NH ₂ .

The description of the partially condensed polyhedral oligomeric silsesquioxane in which at least one of the -Si-O-Si- bonds is introduced into a hydrogen-bondable functional group is the same as described above, and thus detailed description thereof will be omitted.

Light-transmitting substrate 100 comprising a polyimide or poly (imide-amide) copolymer Also, like the optical enhancement layer 200 described above, hydrogen at a position where one or more -Si-O-Si- bonds are broken By further including a partially condensed polyhedral oligomer silsesquioxane in which a functional group capable of binding is introduced, mechanical strength and optical properties can be further improved.

The partially condensed polyhedral oligomeric silsesquioxane in which at least one of the -Si-O-Si- bonds are introduced with hydrogen-bondable functional groups is a polyimide or poly (imide-amide) copolymer in the light transmitting substrate 100 20 parts by mass or less per 100 parts by mass, for example, 15 parts by mass or less per 100 parts by mass of the polyimide copolymer, for example, 10 parts by mass or less per 100 parts by mass of the polyimide copolymer, for example, about 1 part by mass to It may contain about 10 parts by mass.

The thickness of the light transmitting substrate may be 10 μm to 300 μm, for example, 15 μm to 300 μm, for example, 20 μm to 300 μm, for example, 25 μm to 300 μm, for example, 30 Μm to 300 µm, for example 30 µm to 250 µm, for example 30 µm to 200 µm, for example 30 µm to 150 µm, for example 30 µm to 100 µm, for example 30 Μm to 80 μm, for example 30 μm to 70 μm, for example 30 μm to 60 μm, for example 35 μm to 60 μm, for example 35 μm to 55 μm.

As the hard coating layer 300 applied to the laminated film according to an embodiment, any hard coating layer material known in the art may be used, and is not particularly limited. The hard coating layer can increase the surface hardness of the laminated film.

As the hard coating layer 300 material, a material that is cured by heat or light may be used, for example, an acrylate-based polymer, a urethane-based polymer, an epoxy-based polymer, a silicone-based polymer, a polycaprolactone, and a urethane-acrylate copolymer. Polymers, polyrotaxane, silica-containing inorganic hard coating materials, and the like. The acrylate-based polymer may be a polymer of a monomer mixture including a polyfunctional acrylate monomer. Examples of polyfunctional acrylate monomers include trimethylolpropane triacrylate (TMPTA), trimethylolpropaneethoxy triacrylate (TMPEOTA), glycerin propoxylated triacrylate (GPTA), pentaerythritol tetraacrylate (PETA) ), And dipentaerythritol hexaacrylate (DPHA). Urethane-based or acrylate-based polymers and polyfunctional acrylate materials can exhibit excellent adhesion and high productivity.

In one embodiment, the hard coating layer includes a silicone-based polymer, and the silicone-based polymer may include an organopolysiloxane such as silsesquioxane.

1 and 2 show that the hard coating layer 300 is composed of one layer, the hard coating layer may have a multi-layer structure of two or more layers.

The thickness of the hard coating layer 300 is 50 μm or less, for example 1 μm to 50 μm, for example 1 μm to 40 μm, for example 1 μm to 30 μm, for example 3 μm to 30 μm, for example For example 5 μm to 30 μm, for example 5 μm to 25 μm, for example 5 μm to 20 μm, for example 5 μm to 15 μm, for example 5 μm to 10 μm, and the like. Does not work.

Laminate film according to an embodiment for improving the optical properties, mechanical properties, and / or bending properties of the laminated film, in addition to the light transmitting substrate 100, the optical enhancement layer 200, and the hard coating layer 300 Any layer may be further included.

For example, as shown in FIGS. 3 and 4, the laminated film according to one embodiment may further include a back coating layer 400 disposed under the light transmitting substrate 100. In the case of FIG. 3, it shows that the back coating layer 400 is added to the lower portion of the light transmitting substrate 100 of the laminated film of FIG. 1. FIG. 4 shows that a back coating layer 400 is added to the lower portion of the light transmitting substrate 100 of the laminated film of FIG. 2. In the laminated film of FIG. 2, the optical enhancement layer 200 is present under the light transmitting substrate 100. As shown in FIG. 4, the back coating layer 400 is substantially light transmitting substrate ( 100) may be disposed to exist under the optical enhancement layer 200 disposed below.

The back coating layer 400 may be optically colorless and transparent, and may include any material as long as it can adhere well to the adhesive layer or superelastic layer described later and maintain the bending properties of the laminated film. For example, the back coating layer 400 may include the same material as the hard coating layer 300, and materials used as a hard coating layer of a window for a conventional display device may be used without limitation. For example, the back coating layer 400 may include (meth) acrylate-based polymer, polycaprolactone, urethane-acrylate copolymer, polyrotaxane, epoxy resin, siloxane copolymer, perfluoropolyether, or It may include a combination of.

The thickness of the back coating layer 400 is about 30 nm to 300 nm, for example about 40 nm to about 200 nm, for example about 50 nm to about 180 nm, for example about 60 nm to about 150 nm, for example, about 70 nm to about 130 nm, for example, about 80 nm to about 120 nm, for example, may be formed in a range of about 90 nm to about 120 nm, the hard coating layer 300 It can be formed relatively thin compared to.

The refractive index of the back coating layer may be 1.7 or less, for example, 1.6 or less, for example, 1.5 or less, for example, 1.4 or less, for example, 1.3 or less.

The rest of the layers except for the back coating layer 400 are the same as those described with reference to FIGS. 1 and 2, and thus detailed descriptions thereof will be omitted.

As described above, the laminated film may further include an adhesive layer or a superelastic layer 500 under the back coating layer 400. 5 is a view schematically showing a configuration further comprising an adhesive layer or a super-elastic layer 500 under the back coating layer 400 of the laminated film of FIG. 3, and FIG. 6 is a back coating layer of the laminated film of FIG. 400 is a view schematically showing a configuration further comprising an adhesive layer or a superelastic layer 500 on the lower portion.

Meanwhile, the laminated film according to the embodiment does not include the back coating layer 400, and may further include an adhesive layer or a superelastic layer 500 under the light transmitting substrate 100. 7 and 8 schematically show this.

7 is a view schematically showing that the adhesive layer or the superelastic layer 500 is additionally included under the light transmitting substrate 100 in the laminated film of FIG. 1, and FIG. 8 is a light in the laminated film of FIG. 2. It is a diagram schematically showing that the optical enhancement layer 200 is present under the transmissive substrate 100 and an adhesive layer or a superelastic layer 500 is additionally included under the optical enhancement layer 200. That is, the laminated film according to the embodiment may further include an adhesive layer or a superelastic layer 500 in a state in which the back coating layer 400 is included or not included in the lower portion of the light transmitting substrate 100. have. By further including the adhesive layer or the superelastic layer 500, the laminated film may be adhered to the front portion of a display device (not shown), or may be adhered to an additional film.

The adhesive layer may include a PSA adhesive, and the superelastic layer may include, but is not limited to, superelastic materials such as polyurethane and polydimethyl siloxane (PDMS).

On the other hand, since the adhesive layer or the superelastic layer 500 may cause deterioration of optical properties and hardness, the thinner the thickness of these layers, the better. For example, the thickness of the adhesive layer or superelastic layer 500 may be 50 μm or less, for example, 10 μm to 40 μm, for example, 10 μm to 30 μm, and is not limited thereto.

Since the structure of the rest of the laminated film except the adhesive layer or the superelastic layer 500 is the same as described above, detailed description thereof will be omitted.

1 to 8, the laminated film according to one embodiment, in addition to the light transmitting substrate 100, the optical enhancement layer 200, and the hard coating layer 300, desired uses or characteristics to be implemented, etc. Accordingly, the back coating layer 400, or any layer, such as an adhesive layer or a superelastic layer 500, may be further combined to thereby improve mechanical properties, optical properties, and / or flexural properties of the laminated film. Can be supplemented. A person having ordinary skill in the art selects, combines, and modifies well-known layers in various forms, including the above-described layers, according to a desired use and function in manufacturing a laminated film according to one embodiment. It can be included, it is obvious that the selection, combination, and modification of these various forms are also within the scope of the present invention.

According to one embodiment, the laminated film including the light transmitting substrate 100, the optical enhancement layer 200, and the hard coating layer 300 has a light transmittance of 90% or more in a wavelength range of 350 nm to 750 nm , Yellowness (YI) may be less than 3, haze may be 2 or less. In addition, the laminated film according to the embodiment does not show a rainbow phenomenon on the surface with the naked eye, and even after attaching the laminated film to the black reflector, when the reflectance is measured at an incident angle of 45 degrees, the average amplitude in the visible light region is It can be confirmed that the rainbow phenomenon was suppressed by appearing at 0.1% or less.

That is, the laminated film according to one embodiment in the laminated film including the light-transmitting substrate 100 and the hard coating layer 300 having different refractive indexes, a polyimide-based copolymer having a refractive index between the refractive index values of the two layers By including the optical enhancement layer comprising the light-transmitting substrate 100 and the hard coating layer 300 or between the light-transmitting substrate 100, by including the hard coating layer 300 in a position facing the , While implementing excellent optical properties, it can be seen that it is possible to provide a laminated film with improved appearance quality by suppressing the rainbow phenomenon on the surface.

The laminated film according to one embodiment, after preparing or purchasing a film comprising a polyimide or poly (imide-amide) copolymer as the light transmitting substrate 100, one surface of the film of the light transmitting substrate 100 A solution of the polyimide-based copolymer forming the optical improvement layer 200 is coated, and a solvent is removed from the coating to form the optical improvement layer 200, and then, on the surface of the optical improvement layer 200, Alternatively, a hard coating solution forming a hard coating layer 300 is coated on the other surface of the light transmitting substrate 100 on the opposite side to the side where the optical enhancement layer 200 is located, and the solvent is dried from the hard coating solution. It can be produced by curing to form a hard coating layer 300.

Films comprising polyimide or poly (imide-amide) copolymers as light transmissive substrate 100 are prepared using polyimide and / or poly (imide-amide) copolymer production methods known in the art. Polyimide and / or poly (imide-amide) copolymers can be prepared and easily produced by making a film therefrom, or by purchasing commercially available polyimide or poly (imide-amide) copolymer films You can also use

The imide structural unit constituting the polyimide or poly (imide-amide) copolymer can be prepared by polymerizing a diamine and a dianhydride or diisocyanate compound in an organic solvent. The diamine, dianhydride, and diisocyanate are not limited to a specific compound, and a polyimide or poly that satisfies optical properties and mechanical properties suitable for use as the light transmitting substrate 100 of the laminated film according to one embodiment. (Imide-amide) Any diamine, dianhydride, and diisocyanate compound can be appropriately selected and used as long as the copolymer can be produced. Examples of the diamine compound include hexamethylene diamine; m-phenylene diamine; p-phenylene diamine; 1,3-bis (4-aminophenyl) propane; 2,2-bis (4-aminophenyl) propane; 4,4'-diamino-diphenyl methane; 1,2-bis (4-aminophenyl) ethane; 1,1-bis (4-aminophenyl) ethane; 2,2'-diamino-diethyl sulfide; Bis (4-aminophenyl) sulfide; 2,4'-diamino-diphenyl sulfide; Bis (3-aminophenyl) sulfone; Bis (4-aminophenyl) sulfone; 4,4'-diamino-dibenzyl sulfoxide; Bis (4-aminophenyl) ether; Bis (3-aminophenyl) ether; Bis (4-aminophenyl) diethyl silane; Bis (4-aminophenyl) diphenyl silane; Bis (4-aminophenyl) ethyl phosphine oxide; Bis (4-aminophenyl) phenyl phosphine oxide; Bis (4-aminophenyl) -N-phenyl amine; Bis (4-aminophenyl) -N-methylamine; 1,2-diamino-naphthalene; 1,4-diamino-naphthalene; 1,5-diamino-naphthalene; 1,6-diamino-naphthalene; 1,7-diamino-naphthalene; 1,8-diamino-naphthalene; 2,3-diamino-naphthalene; 2,6-diamino-naphthalene; 1,4-diamino-2-methyl-naphthalene; 1,5-diamino-2-methyl-naphthalene; 1,3-diamino-2-phenyl-naphthalene; 4,4'-diamino-biphenyl; 3,3'-diamino-biphenyl; 3,3'-dichloro-4,4'-diamino-biphenyl; 3,3'-dimethyl-4,4'-diamino-biphenyl; 3,3'-dimethyl-4,4'-diamino-biphenyl; 3,3'-dimethoxy-4,4'-diamino-biphenyl; 4,4'-bis (4-aminophenoxy) -biphenyl; 2,4-diamino-toluene; 2,5-diamino-toluene; 2,6-diamino-toluene; 3,5-diamino-toluene; 1,3-diamino-2,5-dichloro-benzene; 1,4-diamino-2,5-dichloro-benzene; 1-methoxy-2,4-diamino-benzene; 1,4-diamino-2-methoxy-5-methyl-benzene; 1,4-diamino-2,3,5,6-tetramethyl-benzene; 1,4-bis (2-methyl-4-amino-pentyl) -benzene; 1,4-bis (1,1-dimethyl-5-amino-pentyl) -benzene; 1,4-bis (4-aminophenoxy) -benzene; o-xylylene diamine; m-xylylene diamine; p-xylylene diamine; 3,3'-diamino-benzophenone; 4,4'-diamino-benzophenone; 2,6-diamino-pyridine; 3,5-diamino-pyridine; 1,3-diamino-adamantane; Bis [2- (3-aminophenyl) hexafluoroisopropyl] diphenyl ether; 3,3'-diamino-1,1,1'-diadamantan; N- (3-aminophenyl) -4-aminobenzamide; 4-aminophenyl-3-aminobenzoate; 2,2-bis (4-aminophenyl) hexafluoropropane; 2,2-bis (3-aminophenyl) hexafluoropropane; 2- (3-aminophenyl) -2- (4-aminophenyl) hexafluoropropane; 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane; 2,2-bis [4- (2-chloro-4-aminophenoxy) phenyl hexafluoropropane; 1,1-bis (4-aminophenyl) -1-phenyl-2,2,2-trifluoroethane; 1,1-bis [4- (4-aminophenoxy) phenyl] -1-phenyl-2,2,2-trifluoroethane; 1,4-bis (3-aminophenyl) buta-1-ene-3-yne; 1,3-bis (3-aminophenyl) hexafluoropropane; 1,5-bis (3-aminophenyl) decafluoropentane; And 4,4'-bis [2- (4-aminophenoxyphenyl) hexafluoroisopropyl] diphenyl ether, diaminocyclohexane, bicyclohexyldiamine, 4,4'-diaminocyclohexylmethane, and Diamino fluorene, and the like. Such diamine compounds are commercially available or can be synthesized by a known method.

For example, the diamine may be a compound having the following structural formula:

In one embodiment, the diamine is 2, 2'-bis (trifluoromethyl) benzidine (2, 2'-bis (trifluoromethyl) benzidine: TFDB) and / or 3,3-bis (1-hydroxy-1 -Trifluoromethyl-2,2,2-trifluoroethyl) -4,4'-methylenedianiline (3,3'-Bis (1-hydroxy-1-trifluoromethyl-2,2,2-trifluoroethyl) -4,4'-methylenedianiline, MFA-MDA).

The dianhydride may be a tetracarboxylic dianhydride, and these compounds are 3,3 ', 4,4'-biphenyl tetracarboxylic dianhydride (3,3', 4,4'-biphenyl tetracarboxylic dianhydride , BPDA), bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (bicycle [2.2.2] oct-7-ene-2,3,5, 6-tetracarboxylic dianhydride (BTDA), 3,3 ', 4,4'-biphenylsulfone tetracarboxylic dianhydride (3,3', 4,4'-diphenylsulfone tetracarboxylic dianhydride, DSDA),, 4,4 ' -(Hexafluoroisopropylidene) diphthalic anhydride (4,4 '-(hexafluoroisopropylidene) diphthalic anhydride, 6FDA), 4,4'-oxydiphthalic anhydride (ODPA) ), Pyromellitic dianhydride (PMDA), 4-((2,5-dioxotedrahydrofuran-3-yl) -1,2,3,4-tetranaphthalene-1,2 -Dicarboxylic anhydride (4- (2,5-dioxotetrahydrofuran-3-yl) -1,2, 3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride (DTDA), 1,2,4,5-benzene tetracarboxylic dianhydride; 1,2,3,4-benzene tetracarboxylic dianhydride; 1, 4-bis (2,3-dicarboxyphenoxy) benzene dianhydride; 1,3-bis (3,4-dicarboxyphenoxy) benzene dianhydride; 1,2,4,5-naphthalene tetracarboxylic dianhydride Water; 1,2,5,6-naphthalene tetracarboxylic dianhydride; 1,4,5,8-naphthalene tetracarboxylic dianhydride; 2,3,6,7-naphthalene tetracarboxylic dianhydride; 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride; 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride; 2,3,6, 7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic dianhydride; 3,3 ', 4,4'-biphenyl tetracarboxylic dianhydride; 2,2 ', 3,3'-biphenyl tetracarboxylic dianhydride; 4,4'-bis (3,4-dicarboxylphenoxy) diphenyl dianhydride; Bis (2,3-dicarboxyphenyl) ether dianhydride; 4,4'-bis (2,3-dicarboxylphenoxy) diphenyl ether dianhydride; 4,4'-bis (3,4-dicarboxylphenoxy) diphenyl ether dianhydride; Bis (3,4-dicarboxyphenyl) sulfide dianhydride; 4,4'-bis (2,3-dicarboxphenoxy) diphenylsulfide dianhydride; 4,4'-bis (3,4-dicarboxylphenoxy) diphenyl sulfide dianhydride; Bis (3,4-dicarboxyphenyl) sulfone dianhydride; 4,4'-bis (2,3-dicarboxylphenoxy) diphenylsulfone dianhydride; 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride; 3,3 ', 4,4' '-benzophenone tetracarboxylic dianhydride; 2,2 ', 3,3'-benzophenone tetracarboxylic dianhydride; 2,3,3'4'-benzophenone tetracarboxylic dianhydride; 4,4'-bis (3,4-dicarboxyphenoxy) benzophenone dianhydride; Bis (2,3-dicarboxyphenyl) m ethane dianhydride; Bis (3,4-dicarboxyphenyl) methane dianhydride; 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride; 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride; 1,2-bis (3,4-dicarboxyphenyl) ethane dianhydride; 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride; 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride; 2,2-bis [4- (2,3-dicarboxyphenoxy) phenyl] propane dianhydride; 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride; 4- (2,3-dicarboxyphenoxy) -4 '-(3,4-dicarboxyphenoxy) diphenyl-2,2-propane dianhydride; 2,2-bis [4- (3,4-dicarboxyphenoxy-3,5-dimethyl) phenyl] propane dianhydride; 2,3,4,5-thiophene tetracarboxylic dianhydride; 2,3,5,6-pyrazine tetracarboxylic dianhydride; 1,8,9,10-phenanthrene tetracarboxylic dianhydride; 3,4,9,10-perylene tetracarboxylic dianhydride; 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride; 1,3-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride; 1,1-bis (3,4-dicarboxyphenyl) -1-phenyl-2,2,2-trifluoroethane dianhydride; 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] hexafluoropropane dianhydride; 1,1-bis [4- (3,4-dicarboxyphenoxy) phenyl] -1-phenyl-2,2,2-trifluoro ethane dianhydride; And 4,4'-bis [2- (3,4-dicarboxyphenyl) hexafluoroisopropyl] diphenyl ether dianhydride, but is not limited to these. These dianhydride compounds are commercially available or can be synthesized by known methods.

In one embodiment, the tetracarboxylic dianhydride is 3,3 ', 4,4'-biphenyl tetracarboxylic dianhydride (3,3', 4,4'-biphenyl tetracarboxylic dianhydride, BPDA), 4,4 '-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), or mixtures thereof.

On the other hand, as a known polyamide production method, a low-temperature solution polymerization method, an interfacial polymerization method, a melt polymerization method, a solid-phase polymerization method, etc. are known. The amide structural unit represented by Chemical Formula 4 can be formed by reacting a carboxylic acid dihalide and a diamine in the inside.

The carboxylic acid dihalide includes terephthaloyl chloride (TPCl), isophthaloyl chloride (IPCl), biphenyl dicarbonyl chloride (BPCl), naphthalene dicarbonyl chloride, Terphenyl dicarbonyl chloride, 2-fluoro-terephthaloyl chloride, adipoyl chloride, sebacoyl chloride, and the like.

In one embodiment, the carboxylic acid dihalide may be terephthaloyl chloride (TPCl).

The diamine for forming the amide structure may use the same diamine compound as the diamine that can be used to form the imide structure. That is, the amide structure may be formed using one or more diamines that are the same or different among the diamine compounds exemplified above.

In one embodiment, the diamine for forming the amide structure together with the carboxylic acid dihalide is 2, 2'-bis (trifluoromethyl) benzidine (2, 2'-bis (trifluoromethyl) benzidine: TFDB) and / or Or 3,3-bis (1-hydroxy-1-trifluoromethyl-2,2,2-trifluoroethyl) -4,4'-methylenedianiline (3,3'-Bis (1-hydroxy -1-trifluoromethyl-2,2,2-trifluoroethyl) -4,4'-methylenedianiline, MFA-MDA).

As the aprotic polar solvent, For example, sulfoxide-based solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide-based solvents such as N, N-dimethylformamide and N, N-diethylformamide, N, N-dimethylacetamide, Acetamide-based solvents such as N, N-diethylacetamide, pyrrolidone-based solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, phenol, o-, m- or p And phenol-based solvents such as cresol, xylenol, halogenated phenol, and catechol, or hexamethylphosphorylamide, γ-butyrolactone, etc., and these may be used alone or in combination. However, the present invention is not limited thereto, and aromatic hydrocarbons such as xylene and toluene may be used.

The amide structural unit and the imide structural unit are first reacted by adding diamine and dicarboxylic acid dihalide forming an amide structural unit in the same reactor, and thereafter, diamine and dianhydride forming imide structural units. Poly (amide-amic acid) copolymer can be prepared by adding and reacting.

Or, after reacting diamine forming a amide structural unit with dicarboxylic acid dihalide to prepare an amide oligomer having both ends terminated with an amino group, using this as a diamine monomer, dianhydride is added thereto to add poly (amide- Amic acid) copolymers can also be prepared. According to the latter method, a precipitation process for removal of HCl generated in the amide formation process can be omitted, so that the process time can be shortened, and the yield of the final product poly (amide-imide) copolymer is also increased. You can.

The polyamic acid or poly (amic acid-amide) copolymer prepared as described above may be prepared as a polyimide or poly (imide-amide) copolymer by undergoing a dehydration / closure reaction of amic acid. It is also well known to cast a solution containing an imide-amide) copolymer onto a support by a known method, then dry it and then harden it by a method such as heating to produce a molded article such as a film.

The polyimide-based copolymer solution for forming the optical improvement layer 200 is coated on the film surface including the polyimide or poly (imide-amide) copolymer prepared as described above. The manufacturing method of the polyimide-based copolymer solution is substantially the same as the manufacturing method of the polyimide or poly (imide-amide) copolymer solution for preparing the light-transmitting substrate 100 described above.

For example, when the optical improving layer 200 is a poly (imide-urethane) copolymer containing an imide structural unit and a urethane structural unit, a diol and a diisocyanate compound are polymerized as a monomer for preparing the urethane structural unit. And a poly (imide-urethane) copolymer solution containing both the imide structural unit and the urethane structural unit by further polymerizing by adding tetracarboxylic dianhydride and diamine to form the imide structural unit. Can be produced. The reaction between diol and diisocyanate compounds to form the urethane structural unit is also well known in the art. The types of diols and diisocyanate compounds that can be used are also not particularly limited, and there are no significant problems in implementing optical properties and mechanical properties suitable for use as the optical enhancement layer 200 in the laminated film according to one embodiment. Diol and diisocyanate compounds can be used. These diol and diisocyanate compounds are also synthesized by methods known in the art, or commercially available.

When the optical improving layer 200 includes an imide structural unit and a siloxane structural unit, tetracarboxylic dianhydride and diamine for forming an imide structural unit are mixed and reacted in an organic solvent. Here, diamine As a component, a poly (imide-siloxane) copolymer solution can be easily produced by further reacting by including a siloxane compound containing an amino group at both terminals. The siloxane compound having an amino group at both terminals forms an imide structural unit by polymerizing with tetracarboxylic dianhydride, and thus, an imide structural unit by reaction between a diamine compound not containing siloxane and tetracarboxylic dianhydride. Polymerized together, a poly (imide-siloxane) copolymer can be prepared. Compounds containing an amino group at both ends of the siloxane compound can be easily synthesized or commercially available through methods well known to those skilled in the art. A person having ordinary skill in the art can easily select a compound modified at both ends with an amino group as a siloxane compound suitable for realizing desired mechanical properties and optical properties. For example, the siloxane compound may be represented by the following Chemical Formula 3-1:

(Formula 3-1)

In Chemical Formula 3-1,

R ^a to R ^f , L ¹ , L ² , and m are all the same as defined in Chemical Formula 3.

When the optical enhancement layer 200 is a poly (imide-amide) copolymer containing an imide structural unit and an amide structural unit, the light transmitting substrate 100 may include a poly (imide-amide) copolymer. Since it is the same as the case, detailed description of it is omitted.

The solution of the poly (imide-urethane) copolymer, poly (imide-siloxane) copolymer, or poly (imide-amide) copolymer prepared as above is further diluted with a solvent or the like to yield polyimide or poly (already De-amide) by coating the film surface, which is a light-transmitting substrate 100 containing a copolymer, and drying, the optical improving layer 200 of the laminated film according to one embodiment may be easily formed.

The method for preparing the solution for forming the hard coating layer 300 is not particularly limited, and a polymer solution that can be used as a hard coating material is prepared using a method well known to those skilled in the art. Alternatively, commercially available materials may be used. For example, when the hard coating layer 300 includes a siloxane-based polymer, a polycondensation reaction of a silane compound that can be made of polysiloxane by a dehydration condensation reaction in a solvent, and a solution containing the polysiloxane prepared therefrom Can be used as a solution for forming a hard coating. Alternatively, when the hard coating layer 300 includes an acrylate-based polymer, a commercially available acrylate polymer may be dissolved in an appropriate solvent, or an acrylate monomer may be polymerized to prepare an acrylate-based polymer solution. have. Since all of these methods are well known to those skilled in the art, detailed descriptions thereof will be omitted.

A light-transmitting substrate 100 including a polyimide or poly (imide-amide) copolymer prepared by the above method, and an optical enhancement layer 200 present on one side of the light-transmitting substrate 100, And the light on the opposite side of the side where the optical enhancement layer 200 is located so as to be on the optical enhancement layer 200 or to face the optical enhancement layer 200 with the light transmitting substrate 100 therebetween. It includes a hard coating layer 300 present on the surface of the transmissive substrate 100, the optical enhancement layer 200 comprises a polyimide-based copolymer, the refractive index of the optical enhancement layer 200 is the light transmission The laminated film having a value between the refractive index of the substrate 100 and the refractive index of the hard coating layer 300 is suppressed by the occurrence of interfacial reflection and optical interference fringe due to the difference in the refractive index between the layers, thereby improving optical properties and color visibility and appearance quality This can be improved. Therefore, such a laminated film can be advantageously used as a window film of a display device.

Hereinafter, the embodiments will be described in more detail through Examples and Comparative Examples. The following Examples and Comparative Examples are for the purpose of explanation, and the scope of the present invention is not limited thereby.

Example

Synthesis Example 1: Preparation of amide structural unit-containing oligomer

According to Reaction Scheme 1, TFDB (2,2'-bis (trifluoromethyl) benzidine (2,2'-bis (trifluoromethyl) benzidine)) is bonded to both ends of TPCL (terephthalic acid dichloride) to form an aramid structure. An oligomer containing amide structural units to form is prepared:

 (Scheme 1)

That is, 2,2'-bis (trifluoromethyl) benzidine, TFDB in 700g of N, N-dimethylacetamide as a solvent in a round bottom flask ) After dissolving 1 molar equivalent (0.122 mole, 39.2 g) and 2.8 molar equivalent of pyridine (0.343 mole, 27.11 g), the remaining TFDB is completely dissolved by adding 50 ml of dimethylaceamide (DMAC). To the TFDB solution, terephthaloyl chloride (TPCL) 0.7 molar equivalents (0.086 molar, 17.4 g) are divided in 4 portions and mixed and stirred vigorously for 15 minutes.

The resulting solution was stirred in a nitrogen atmosphere for 2 hours, then placed in a 7 L NaCl solution containing 350 g of NaCl and stirred for 10 minutes. The solid is filtered, resuspended and re-filtered twice with 5 L of deionized water. Subsequently, the final filtrate on the filter is appropriately pressurized to remove residual water as much as possible, and dried under vacuum at 90 ° C. for 48 hours to obtain an amide structural unit-containing oligomer represented by “amide oligomer” in Reaction Scheme 1. The number average molecular weight of the obtained oligomer is about 1,400.

Preparation Examples 1 to 4: Preparation of polyimide-based copolymer solution for optical improvement layer

Preparation Example 1: Preparation of poly (imide-urethane) copolymer solution

2.52 g (0.0279 mol) of butanediol (BD) and 12.4 g (0.0559 mol) of isophorone diisocyanate (IPDI), and DBTDL in a 250 ml 4-neck double wall reactor with mechanical stirrer and nitrogen inlet After adding (Dibutyltin dilaurate), the temperature was gradually increased and stirred at 70 ° C for 4 hours to react. After the reaction was completed, the reactor was cooled to 25 ° C, and 94 grams of dimethylacetamide (DMAc), 2,2'-bis (trifluoromethyl) benzidine (2,2'-bis (trifluoromethyl) benzidine, TFDB) 8.95 g (0.0279 mol), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (3,3', 4,4'-biphenyltetracarboxylic dianhydride, BPDA) 2.46 g (0.0084 mol), and 2,2-bis- (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (2,2-bis- (3,4-dicarboxyphenyl hexafluoropropane dianhydride, 6FDA) 8.70 g (0.0196 mol) was added and 24 After stirring for an hour, 2.3 g of pyridine and 7.9 g of acetic anhydride were added and stirred for 24 hours to obtain a poly (imide-urethane) copolymer solution having a solid content concentration of 25% by weight.

Preparation Example 2: Preparation of poly (imide-siloxane) copolymer solution

After adding 58 g of dimethylacetamide (DMAc) to a 250 ml 4-neck double wall reactor equipped with a mechanical stirrer and nitrogen inlet, the temperature was adjusted to 25 ° C., followed by 2,2′-bis (trifluoromethyl) benzidine (2, 5.7 g ( 0.018 mol) of 2'-bis (trifluoromethyl) benzidine, TFDB ) was dissolved, and the solution was maintained at 25 ° C. To this, 3.9 g (0.0045 mol) of polydimethylsiloxane (DMS-A11, Gelest) capped with an aminopropyl group at both ends was dissolved in 26 g of tetrahydrofuran (THF). To the solution, 1.97 g (0.0067 mol) of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (3,3', 4,4'-biphenyltetracarboxylic dianhydride, BPDA ), and 2,2 -Bis- (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (2,2-bis- (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 6FDA) 6.94 g (0.0156 mol) was added and stirred for 48 hours. Then, 1.8 g of pyridine and 6.8 g of acetic anhydride were added and stirred for 24 hours to obtain a poly (imide-siloxane) copolymer solution having a solid content concentration of 17% by weight.

Preparation Example 3: Preparation of poly (imide-amide-siloxane) copolymer solution

After adding 120 g of dimethylacetamide (DMAc) to a 250 ml 4-neck double wall reactor equipped with a mechanical stirrer and nitrogen inlet to set the temperature to 25 ° C., the amide structural unit-containing oligomer prepared in Synthesis Example 1 was 21.36 g (0.015 mol), 2,2'-bis (trifluoromethyl) benzidine (2,2'-bis (trifluoromethyl) benzidine, TFDB) 0.37g ( 0.0011mol ), and 1,3-bis (3-aminopropyl) -Tetramethyldisiloxane {1,3-bis (3-aminopropyl) -tetramethyldisiloxane: DSX } 0.673 g (0.0027 mol) was dissolved, and the solution was maintained at 25 ° C. 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (3,3', 4,4'-biphenyltetracarboxylic dianhydride, BPDA ) 1.59g (0.0054mol), and 2,2- After adding bis- (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (2,2-bis- (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 6FDA) 6g (0.013mol) and stirring for 48 hours. , 1.5 g of pyridine, and 5.83 g of acetic anhydride were added and stirred for 24 hours to obtain a poly (imide-amide-siloxane) copolymer solution having a solid content concentration of 20% by weight.

Preparation Example 4: Preparation of poly (imide-amide) copolymer solution

After adding 120 g of dimethylacetamide (DMAc) to a 250 ml 4-neck double wall reactor equipped with a mechanical stirrer and nitrogen inlet to set the temperature to 25 ° C., 21.36 g (0.015 mol) of the amide structural unit-containing oligomer prepared in Synthesis Example 1 ), 2,2'-bis (trifluoromethyl) benzidine (2,2'-bis (trifluoromethyl) benzidine, TFDB ) 0.37g ( 0.0011mol ), and 3,3-bis (1-hydroxy-1) -Trifluoromethyl-2,2,2-trifluoroethyl) -4,4'-methylenedianiline (3,3'-Bis (1-hydroxy-1-trifluoromethyl-2,2,2-trifluoroethyl) -4,4'-methylenedianiline, MFA-MDA ) 8.87 g (0.0167 mol) was dissolved, and the solution was kept at 25 ° C. To this solution, 1.23 g (0.0042 mol) of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (3,3', 4,4'-biphenyltetracarboxylic dianhydride, BPDA ), and 2,2- 9.28 g (0.021 mol) of bis- (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (2,2-bis- (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 6FDA ) was added and stirred for 48 hours. Thereafter, 1.98 g of pyridine and 7.68 g of acetic anhydride were added and stirred for 24 hours to obtain a poly (imide-amide) copolymer solution having a solid content concentration of 20% by weight.

Preparation Example 5: Preparation of a solution for forming a hard coating layer

Preparation Example 5-1: Preparation of silsesquioxane

In a 100 ml double-jacketed reaction vessel, 20 ml of ethyl alcohol (Samjeon Chemical) and 17.5 g of a tetramethylammonium hydroxide solution (TMAH: tetramethylammonium hydroxide solution diluted by 1 wt%) were added and mixed. While mixing, 26.5 ml of (3-glycidyloxypropyl) trimethoxysilane (Sigma-Aldrich) was added and mixed at room temperature for 6 hours. Subsequently, the temperature was raised to 60 ° C., and 40 ml of toluene (Sigma-Aldrich) was added to the mixture and mixed for 6 hours. When the mixing is completed, the reaction product solution is washed with saturated sodium chloride solution (Samjeon Chemical Co., Ltd.), and residual moisture is removed using anhydrous forgetmedium (sodium sulfate anhydrous, Samjeon Chemical). Subsequently, residual solvents such as toluene remaining in the reaction product are removed using an evaporator (Korea Science) and a vacuum oven (Korea Science).

Preparation Example 5-2: Preparation of silsesquioxane

In a 100 ml double-jacketed reactor, 20 ml of ethyl alcohol (Samjeon Chemical) and 17.5 g of a solution of tetramethylammonium hydroxide (TMAH, manufactured by Sigma-Aldrich) diluted with 1 wt% are added and mixed. While mixing, 18.2 ml of [8- (glycidyloxy) -n-octyl] trimethoxysilane ([8- (Glycidyloxy) -n-octyl] trimethoxysilane, TCI) was added and mixed at room temperature for 6 hours. Subsequently, the temperature was raised to 60 ° C., and 40 ml of toluene (Sigma-Aldrich) was added to the mixture and mixed for 6 hours. When the mixing is completed, the reaction product solution is washed with saturated sodium chloride solution (Samjeon Chemical), and the residual moisture is removed using anhydrous forget-me-not (sodium sulfate anhydrous). Residual solvent such as toluene remaining in the reaction product is removed using an evaporator (Daehan Science) and a vacuum oven (Daehan Science).

Preparation Example 5-3: Preparation of hard coating solution

Silosequioxane obtained in Preparation Example 5-1, silsesquioxane obtained in Preparation Example 5-2, and a cationic polymerizable organic compound represented by the following Chemical Formula A in methyl isobutyl ketone of 40:40:20 Add to the weight ratio and stir. Here, the content (solid content) of the silsesquioxane obtained in Preparation Example 5-1, the silsesquioxane obtained in Preparation Example 5-2, and the cationic polymerizable organic compound represented by Formula A below is It is 50% based on the total weight. Here, Irgacure 250 (BASF, Inc.) as a cationic initiator was added in an amount of 2 parts by weight relative to 100 parts by weight of the solid content, and KY-1203 (Shin-Etsu), a surface property control agent, was added to 100 parts by weight of the solid content. It is added in an amount of 0.1 parts by weight, and mixed until uniform to prepare a hard coating solution.

(Formula A)

The refractive index of the hard coating layer prepared from the hard coating solution prepared according to the present manufacturing example is 1.5. The refractive index was set by a Gen-Osc model in the visible light region with an Ellipsometer (M-2000, J. A. Woollam) to take a value at a wavelength of 550 nm.

Production Example 6: Preparation of a light transmitting substrate film

101.86 ml of dimethylacetamide (DMAc) was added to a 250 ml 4-neck double wall reactor with a mechanical stirrer and nitrogen inlet, preheated to 30 ° C., and 12.6 g of an amide structural unit-containing oligomer prepared in Synthesis Example 1 (0.0155 mol) was added. The solution was stirred at 30 ° C. under nitrogen atmosphere until the oligomer was completely dissolved. Then, 4.1309 g (0.0093 mol) of 6FDA and 1.8239g (0.0062 mol) of BPDA were slowly added. After further adding 10 ml of DMAc, the solution was stirred for 48 hours, and then 4.75 g of acetic anhydride and 3.68 g of pyridine were added and stirred for 24 hours to obtain a poly (imide-amide) copolymer solution.

The obtained poly (imide-amide) copolymer solution was coated on a glass plate, cast, and dried on an 80 ° C hot plate for one hour to remove the solvent, and then the coated glass plate was placed in an oven, and at room temperature to 250 ° C, 3 minutes per minute. Heat treatment is carried out at a heating rate of ℃. Thereafter, the mixture was cooled slowly, and finally the poly (imide-amide) copolymer film was separated from the glass plate to obtain a poly (imide-amide) copolymer film having a thickness of about 50 μm.

The obtained poly (imide-amide) copolymer film had a refractive index of 1.68. The refractive index was set by a Gen-Osc model in the visible light region with an Ellipsometer (M-2000, J. A. Woollam) to take a value at a wavelength of 550 nm.

Examples and Comparative Examples: Preparation of laminated film

Example 1

The poly (imide-urethane) copolymer solution prepared in Preparation Example 1 was diluted to 10% by weight in methyl isobutyl ketone (MIBK), and the poly (imide-amide) prepared in Preparation Example 6 was prepared. After bar coating on the copolymer film, it is removed from the solvent in a drying oven to form a polymer film of about 1 μm thickness.

Subsequently, on the polymer film, the hard coating solution prepared in Preparation Example 5-3 was bar-coated, and the solvent was removed from the drying oven, followed by curing at 380 mJ / cm 2 using a UV curing machine (LC6B, Fusion UV). By doing so, a hard coating layer having a thickness of 10 μm was formed to prepare a laminated film.

In the obtained laminated film, the refractive index of the optical improvement layer prepared from the poly (imide-urethane) copolymer is 1.58. The refractive index was set with a Gen-Osc model in the visible light region with an Ellipsometer (M-2000, J. A. Woollam) to take a value at a wavelength of 550 nm.

Example 2

The poly (imide-siloxane) copolymer solution prepared in Preparation Example 2 was diluted to 10% by weight in methyl isobutyl ketone (MIBK), and the poly (imide-amide) prepared in Preparation Example 6 was prepared. After bar coating on the copolymer film, it is removed from the solvent in a drying oven to form a polymer film of about 1 μm thickness.

Subsequently, after coating the hard coating solution prepared in Preparation Example 5-3 on the polymer film, and removing the solvent from the drying oven, using a UV curing machine (LC6B, Fusion UV), 100 to 500 mJ / cm 2 By curing in, a hard coating layer having a thickness of 10 μm was formed to prepare a laminated film.

In the obtained laminated film, the refractive index of the optical improving layer prepared from the poly (imide-siloxane) copolymer is 1.59. The refractive index was set with a Gen-Osc model in the visible light region with an Ellipsometer (M-2000, J. A. Woollam) to take a value at a wavelength of 550 nm.

Example 3

The poly (imide-amide-siloxane) copolymer solution prepared in Preparation Example 3 was diluted to 10% by weight in methyl isobutyl ketone (MIBK), and the poly (imide-) prepared in Preparation Example 6 was prepared. Amide) After bar coating on the copolymer film, this is removed from the solvent in a drying oven to form a polymer film of about 1 μm thickness.

Subsequently, the polymer film was bar-coated with the hard coating solution prepared in Preparation Example 5-3, and the solvent was removed from the drying oven, followed by curing at 380 mJ / cm 2 using a UV curing machine (LC6B, Fusion UV). By doing so, a hard coating layer having a thickness of 10 μm was formed to prepare a laminated film.

In the obtained laminated film, the refractive index of the optical improvement layer prepared from the poly (imide-amide-siloxane) copolymer is 1.59. The refractive index was set by a Gen-Osc model in the visible light region with an Ellipsometer (M-2000, J. A. Woollam) to take a value at a wavelength of 550 nm.

Example 4

The poly (imide-amide) copolymer solution prepared in Preparation Example 4 was diluted to 10% by weight in methyl isobutyl ketone (MIBK), and the poly (imide-amide) prepared in Preparation Example 6 was prepared. After bar coating on the copolymer film, it is removed from the solvent in a drying oven to form a polymer film of about 1 μm thickness.

Subsequently, on the polymer film, the hard coating solution prepared in Preparation Example 5-3 was bar-coated, and the solvent was removed from the drying oven, followed by curing at 380 mJ / cm 2 using a UV curing machine (LC6B, Fusion UV). By doing so, a hard coating layer having a thickness of 10 μm was formed to prepare a laminated film.

In the obtained laminated film, the refractive index of the optical improvement layer prepared from the poly (imide-amide) copolymer is 1.60. The refractive index was set with a Gen-Osc model in the visible light region with an Ellipsometer (M-2000, J. A. Woollam) to take a value at a wavelength of 550 nm.

Example 5

To the poly (imide-urethane) copolymer solution prepared in Preparation Example 1, per 100 parts by weight of the poly (imide-urethane) copolymer, trisilanolphenyl silsesquioxane represented by Formula 5-1 above ( A solution containing 5 parts by weight of trisilanolphenyl polyhedral oligomeric silsesquioxane, tsp-POSS) was diluted in methyl isobutyl ketone (MIBK) to a concentration of 10% by weight, and the poly (imide-amide) prepared in Preparation Example 6 was prepared. After bar coating on the copolymer film, it is removed from the solvent in a drying oven to form a polymer film of about 1 μm thickness.

Subsequently, on the polymer film, the hard coating solution prepared in Preparation Example 5-3 was bar-coated, and the solvent was removed from the drying oven, followed by curing at 380 mJ / cm 2 using a UV curing machine (LC6B, Fusion UV). By doing so, a hard coating layer having a thickness of 10 μm was formed to prepare a laminated film.

In the obtained laminated film, the refractive index of the optical improvement layer prepared from a solution in which 5 parts by weight of tsp-POSS was added to 100 parts by weight of the poly (imide-urethane) copolymer was 1.55. The refractive index was set with a Gen-Osc model in the visible light region with an Ellipsometer (M-2000, J. A. Woollam) to take a value at a wavelength of 550 nm.

Example 6

The poly (imide-amide) copolymer solution prepared in Preparation Example 1 was diluted to 10% by weight in methyl isobutyl ketone (MIBK), and the poly (imide-amide) prepared in Preparation Example 6 was prepared. After bar coating on the copolymer film, it is removed from the solvent in a drying oven to form a polymer film of about 1 μm thickness.

Subsequently, the hard coating solution prepared in Preparation Example 5-3 was bar-coated, but this was not coated on the polymer film formed to a thickness of about 1 μm, but at a position opposite to the side where the polymer film was formed, in Production Example 6 After coating the bar on the prepared poly (imide-amide) copolymer film, removing the solvent from the drying oven, and curing at 380 mJ / cm 2 using a UV curing machine (LC6B, Fusion UV), to a thickness of 10 μm. A laminated film is prepared by forming a hard coating layer.

That is, in the laminated film prepared in Example 6, unlike the laminated films according to Examples 1 to 5, the hard coating layer 300 is present on the light transmitting substrate 100, and the optical improvement under the light transmitting substrate 100 is improved. Layer 200 is present.

In the obtained laminated film, the refractive index of the optical improvement layer prepared from the poly (imide-urethane) copolymer is 1.58, as in Example 1.

Comparative Example 1: Preparation of a laminated film having only a hard coating layer on a light transmitting substrate

After coating the hard coating solution prepared in Preparation Example 5-3 on the poly (imide-amide) copolymer film prepared in Preparation Example 6, and removing the solvent from the drying oven, UV curing machine (LC6B, Fusion UV) Cured at 380 mJ / cm 2 using to prepare a laminated film including a hard coating layer having a thickness of 10 μm.

Comparative Example 2: Preparation of a laminated film coated with a commercial primer layer between the light transmitting substrate and the hard coating layer

On the poly (imide-amide) copolymer film prepared in Preparation Example 6, a primer composition having a refractive index of 1.35 sold by Flucon Co., was coated with a bar, and the solvent was removed in a drying oven to form a polymer film having a thickness of about 1 μm. do.

Subsequently, on the polymer film, the hard coating solution prepared in Preparation Example 5-3 was bar-coated, and the solvent was removed from the drying oven, followed by curing at 380 mJ / cm 2 using a UV curing machine (LC6B, Fusion UV). By doing so, a hard coating layer having a thickness of 10 μm was formed to prepare a laminated film.

Evaluation: Evaluation of the optical properties of the film and the presence or absence of Rainbow Mura

The optical properties and presence or absence of Rainbow Mura of the laminated films prepared according to Examples 1 to 6 and Comparative Examples 1 and 2 were evaluated and are shown in Tables 1 and 2 below. Specifically, as the optical properties of the film, transmittance, yellowness index (YI), and haze are measured, and rainbow mura is visually observed, respectively, and measured by the method described below.

(1) Yellow index (YI) and transmittance (Tr (%), transmittance in the range of 350nm to 750nm), respectively, were measured using a spectrophotometer CM-3600d from Minolta, based on a film of about 60㎛ in thickness. And take the value with ASTM D1925.

(2) Haze is measured using a Minolta Co., Ltd. spectrophotometer CM-3600d, and takes the value of ASTM D1003-97.

(3) Rainbow Mura measurement method: To prevent reflection of the back side of the laminated film, the surface opposite to the surface on which the hard coat layer of the laminated film is formed is laminated to a black acrylic plate using 50 μm PSA of 3M, and then under a three-wavelength lamp. The degree of Mura was evaluated as "strong", "about", and "no (none)" by visually observing the hard coating side of the laminated film. In addition, the images of the three-wavelength lamp reflected on the hard coating surface are photographed and are shown in Tables 1 and 2 below.

On the other hand, as a control, the degree of mura, transmittance, YI, and haze of the poly (imide-amide) copolymer film prepared in Preparation Example 6 were also measured, and are shown together in Table 1 below.

Control Comparative Example 1 Comparative Example 2 Example 1 Mura Photo

About Mura radish River River about Transmittance (%) 88 88 89 90 YI 3.0 3.1 2.3 2.8 Haze 0.7 0.9 0.5 0.8

Example 2 Example 3 Example 4 Example 5 Example 6 Mura Photo

About Mura about about about about about Transmittance (%) 90 90 90 90 90 YI 2.3 2.5 2.4 2.8 1.5 Haze 1.0 1.6 1.5 0.8 0.9

As can be seen from Tables 1 and 2, the rainbow mura of the laminated films according to Examples 1 to 6 was weak, whereas the rainbow mura of the laminated films according to Comparative Examples 1 and 2 was very strong. . On the other hand, in the case of a control group that does not form a hard coating layer and is present alone as a poly (imide-amide) copolymer film, Rainbow Mura does not appear at all.

The laminated films according to Examples 1 to 6 have a very weak degree of rainbow mura observed with the naked eye, while the transmittance is 90% or more, and the transmittance is higher than that of Comparative Example 1 and Comparative Example 2 or the control film. In addition, the yellowness index is also lower than that of the film according to Comparative Example 1, which does not include an additional layer between the control film and the hard coating layer and the poly (imide-amide) copolymer substrate. When a commercially available primer layer was interposed between the hard coating layer and the poly (imide-amide) copolymer substrate according to Comparative Example 2, YI was relatively low at 2.3 and haze was also low at 0.8. However, in Comparative Example 2, rainbow mura was strong and the color visibility was poor.

The laminated films according to Examples 1 and 6 include the same poly (imide-amide) copolymer substrate, the same hard coating layer, and the optical enhancement layer of the same composition, but the position of the optical enhancement layer 200 is Different. In the case of the films according to Examples 1 to 5, the order of all poly (imide-amide) copolymer based films (light transmitting substrate 100), optical improving layer 200, and hard coating layer 300 Although laminated with, in Example 6, the optical enhancement layer 200 is not between the poly (imide-amide) copolymer base film 100 and the hard coating layer 300, but between the base film 100 Put on, it is located on the opposite side facing the hard coating layer 300. However, in both Example 1 and Example 6, Rainbow Mura was weakly exhibited, and the optical properties were all excellent. In particular, as in Example 6, the optical enhancement layer 200 with the poly (imide-amide) copolymer base film 100 interposed therebetween, the optical of the laminated film present opposite the hard coating layer 300 The properties, as in Example 1, the optical enhancement layer 200 is superior to the optical properties of the laminated film present between the poly (imide-amide) copolymer base film 100 and the hard coating layer 300 .

As can be seen from the above examples and comparative examples, in the laminated film comprising the poly (imide-amide) copolymer base film 100 and the hard coating layer 300, between the two layers, or the poly ( Imide-amide) When an optical enhancement layer 200 including a polyimide-based copolymer is present on the other side of the hard coating layer 300 with the copolymer-based film 100 therebetween, poly (imide-amide) ) By reducing the difference in refractive index between the copolymer base film 100 and the hard coating layer 300 to reduce interfacial reflection and light interference, the occurrence of rainbow mura is suppressed, resulting in excellent color visibility and excellent appearance quality. A laminated film can be provided. Such a laminated film can be usefully used as a window film of a display device requiring excellent appearance quality.

Although specific embodiments of the present invention have been described through the above, the present invention is not limited to this, and it is possible to carry out various modifications within the scope of the claims and detailed description of the invention and the accompanying drawings. Naturally, it is within the scope of the invention.

Claims (20)

Light transmitting substrate;
Hard coating layer; And
A laminated film comprising an optical improving layer disposed between the light transmitting substrate and the hard coating layer or facing the hard coating layer with the light transmitting substrate interposed therebetween,
The light transmitting substrate includes polyimide, poly (amide-imide) copolymer, or a combination thereof,
The optical improvement layer is a laminated film comprising a copolymer of polyimide. The laminated film of claim 1, wherein the refractive index of the optical enhancement layer has a value between the refractive index of the light transmitting substrate and the refractive index of the hard coating layer. The laminated film of claim 1, wherein the optical enhancement layer has a refractive index between 1.5 and 1.7. The laminated film of claim 1, wherein the polyimide copolymer of the optical enhancement layer comprises (a) an imide structural unit, and (b) a urethane structural unit, a siloxane structural unit, an amide structural unit, or a combination thereof. In claim 4, The imide structural unit is a laminated film represented by the formula (1):
(Formula 1)

In Chemical Formula 1,
D is a substituted or unsubstituted tetravalent C4 to C30 alicyclic organic group, a substituted or unsubstituted tetravalent C6 to C30 aromatic organic group, or a substituted or unsubstituted tetravalent C4 to C30 heteroaromatic organic group, or Combination of these,
The alicyclic organic group, the aromatic organic group, the heteroaromatic organic group, or a combination thereof is a monocyclic ring, a condensed ring in which two or more rings are fused, or two or more rings selected from the monocyclic and condensed rings Single bond, fluorenylene group, -O-, -S-, -C (= O)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,- (CH ₂ ) _p -,-(CF ₂ ) _q- , -C (C _n H _{2n + 1} ) _2- , -C (C _n F _{2n + 1} ) ₂ -,-(CH ₂ ) _p -C ( C _n H _{2n + 1} ) _2- (CH ₂ ) _q -,-(CH ₂ ) _p -C (C _n F _{2n + 1} ) _2- (CH ₂ ) _q- (where 1≤n≤10, 1≤ p≤10, and 1≤q≤10), -C (CF ₃ ) (C ₆ H ₅ )-, or -C (= O) NH-. In claim 4, The urethane structural unit is a laminated film represented by the formula (2):
(Formula 2)
*-(-Y-NH-CO-OZ-)-*
In Chemical Formula 2,
Y and Z are each independently substituted or unsubstituted divalent C1 to C30 aliphatic organic group, substituted or unsubstituted divalent C2 to C30 alicyclic organic group, substituted or unsubstituted C6 to C30 aromatic organic group, or substituted Or an unsubstituted C4 to C30 heteroaromatic organic group, or a combination thereof,
The alicyclic organic group, the aromatic organic group, the heteroaromatic organic group, or a combination thereof is a monocyclic ring, a condensed ring in which two or more rings are fused, or two or more rings selected from the monocyclic and condensed rings Single bond, fluorenylene group, -O-, -S-, -C (= O)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,- (CH ₂ ) _p -,-(CF ₂ ) _q- , -C (C _n H _{2n + 1} ) _2- , -C (C _n F _{2n + 1} ) ₂ -,-(CH ₂ ) _p -C ( C _n H _{2n + 1} ) _2- (CH ₂ ) _q -,-(CH ₂ ) _p -C (C _n F _{2n + 1} ) _2- (CH ₂ ) _q- (where 1≤n≤10, 1≤ p≤10, and 1≤q≤10), -C (CF ₃ ) (C ₆ H ₅ )-, or -C (= O) NH-. In claim 4, wherein the siloxane structural unit is a laminated film represented by the formula (3):
(Formula 3)

In Chemical Formula 3,
R ^a to R ^f are each independently a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C2 to C30 alkenyl group, a substituted or unsubstituted C2 to C30 alkynyl group, a substituted or unsubstituted C1 to C30 An alkoxy group, a substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C6 to C30 aryl group, an epoxy group-containing group, or a combination thereof,
L ¹ and L ² are each independently a single bond, -O-, a substituted or unsubstituted C1 to C30 alkylene group, a substituted or unsubstituted C1 to C30 heteroalkylene group, a substituted or unsubstituted C2 to C30 alkenyl A alkylene group, a substituted or unsubstituted C3 to C30 cycloalkylene group, a substituted or unsubstituted C2 to C30 heterocycloalkylene group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C4 to C30 heteroaryl group, Or combinations thereof,
m is an integer from 0 to 150. In claim 4, the amide structural unit is a laminated film represented by the following formula (4):
(Formula 4)

In Chemical Formula 4,
A, E ¹ and E ² are each independently a substituted or unsubstituted divalent C1 to C30 aliphatic organic group, a substituted or unsubstituted divalent C4 to C30 alicyclic organic group, or a substituted or unsubstituted divalent A C6 to C30 aromatic organic group, a substituted or unsubstituted divalent C4 to C30 heteroaromatic organic group, or a combination thereof,
The alicyclic organic group, aromatic organic group, heteroaromatic organic group, or a combination thereof may be a monocyclic ring, a condensed ring in which two or more rings are bonded, or two or more rings selected from the monocyclic and condensed ring may be a single bond. , Fluorenylene group, -O-, -S-, -C (= O)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,-(CH ₂ ) _p -,-(CF ₂ ) _q- , -C (C _n H _{2n + 1} ) _2- , -C (C _n F _{2n + 1} ) ₂ -,-(CH ₂ ) _p -C (C _n H _{2n + 1} ) _2- (CH ₂ ) _q -,-(CH ₂ ) _p -C (C _n F _{2n + 1} ) _2- (CH ₂ ) _q- (where 1≤n≤10, 1≤p≤ 10, and 1≤q≤10), -C (CF ₃ ) (C ₆ H ₅ )-, or -C (= O) NH-. In claim 1, wherein the optical enhancement layer is one or more -Si-O-Si- incompletely condensed polyvalent oligomeric silsesquioxane (Polyhedral Oligmeric Silsesquioxane: POSS) in which a hydrogen-bondable functional group is introduced at a position where the bond is broken. Laminated film further comprising a. 10. The method of claim 9, The one or more -Si-O-Si- is a partially condensed polyhedral oligomer silsesquioxane in which a hydrogen-bondable functional group is introduced at a position where the bond is broken is a laminated film represented by the following Formula 5 or Formula 6:
(Formula 5) (Formula 6)

In Chemical Formulas 5 and 6,
R are each independently a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C6 to C30 aryl group, or a combination thereof,
R 'is each independently -OH, -SH, or -NH ₂ . The polycondensed polyhedral oligomer silsesquioxane in which the hydrogen-bondable functional group is introduced at a position where the at least one -Si-O-Si- bond is disconnected is 20 per 100 parts by mass of the polyimide copolymer in the optical improvement layer. Laminated film contained below parts by mass. In claim 1, The hard coating layer is an acrylate-based polymer, urethane-based polymer, epoxy-based polymer, silicone-based polymer, polycaprolactone, urethane-acrylate copolymer, polyrotaxane, silica-containing inorganic hard coating material, or A laminated film comprising a combination of these. The laminate film of claim 12, wherein the hard coating layer comprises a silicone-based polymer, and the silicone-based polymer comprises an organopolysiloxane. The method according to claim 1, wherein the light-transmitting substrate comprises a polyimide comprising an imide structural unit represented by Formula 1 below, or an imide structural unit represented by Formula 1 below, and an amide structural unit represented by Formula 4 below. Laminated films comprising poly (amide-imide) copolymers, or combinations thereof:
(Formula 1)

In Chemical Formula 1,
D is a substituted or unsubstituted tetravalent C4 to C30 alicyclic organic group, a substituted or unsubstituted tetravalent C6 to C30 aromatic organic group, or a substituted or unsubstituted tetravalent C4 to C30 heteroaromatic organic group, or Combination of these,
The alicyclic organic group, the aromatic organic group, the heteroaromatic organic group, or a combination thereof is a monocyclic ring, a condensed ring in which two or more rings are bonded, or two or more rings selected from the monocyclic and condensed rings Single bond, fluorenylene group, -O-, -S-, -C (= O)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,- (CH ₂ ) _p -,-(CF ₂ ) _q- , -C (C _n H _{2n + 1} ) _2- , -C (C _n F _{2n + 1} ) ₂ -,-(CH ₂ ) _p -C ( C _n H _{2n + 1} ) _2- (CH ₂ ) _q -,-(CH ₂ ) _p -C (C _n F _{2n + 1} ) _2- (CH ₂ ) _q- (where 1≤n≤10, 1≤ p≤10, and 1≤q≤10), -C (CF ₃ ) (C ₆ H ₅ )-, or -C (= O) NH-;
(Formula 4)

In Chemical Formula 4,
A, E ¹ and E ² are, each independently, a substituted or unsubstituted divalent C1 to C30 aliphatic organic group, a substituted or unsubstituted divalent C4 to C30 alicyclic organic group, a substituted or unsubstituted divalent A C6 to C30 aromatic organic group, a substituted or unsubstituted divalent C4 to C30 heteroaromatic organic group, or a combination thereof,
The alicyclic organic group, aromatic organic group, heteroaromatic organic group, or a combination thereof may be a monocyclic ring, a condensed ring in which two or more rings are bonded, or two or more rings selected from the monocyclic and condensed ring may be a single bond. , Fluorenylene group, -O-, -S-, -C (= O)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,-(CH ₂ ) _p -,-(CF ₂ ) _q- , -C (C _n H _{2n + 1} ) _2- , -C (C _n F _{2n + 1} ) ₂ -,-(CH ₂ ) _p -C (C _n H _{2n + 1} ) _2- (CH ₂ ) _q -,-(CH ₂ ) _p -C (C _n F _{2n + 1} ) _2- (CH ₂ ) _q- (where 1≤n≤10, 1≤p≤ 10, and 1≤q≤10), -C (CF ₃ ) (C ₆ H ₅ )-, or -C (= O) NH-. The laminated film of claim 1, wherein the thickness of the light transmitting substrate is 30 μm to 300 μm, the thickness of the hard coating layer is 1 μm to 30 μm, and the thickness of the optical enhancement layer is 0.1 μm to 10 μm. The laminated film of claim 1, wherein a transmittance of the laminated film is 90% or more. In claim 1, YI of the laminated film is less than 3 laminated film. The laminated film of claim 1, wherein the laminated film has a haze of 2 or less. The laminated film of claim 1, wherein the laminated film has an average amplitude of 0.1% or less in a visible region when measuring reflectance at an incident angle of 45 degrees after attaching the laminated film to a black reflector. A display device comprising the laminated film according to any one of claims 1 to 19.

Images